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      1 /*
      2  * Copyright 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef ANDROID_HARDWARE_HWCOMPOSER2_H
     18 #define ANDROID_HARDWARE_HWCOMPOSER2_H
     19 
     20 #include <sys/cdefs.h>
     21 
     22 #include <hardware/hardware.h>
     23 
     24 #include "hwcomposer_defs.h"
     25 
     26 __BEGIN_DECLS
     27 
     28 /*
     29  * Enums
     30  *
     31  * For most of these enums, there is an invalid value defined to be 0. This is
     32  * an attempt to catch uninitialized fields, and these values should not be
     33  * used.
     34  */
     35 
     36 /* Display attributes queryable through getDisplayAttribute */
     37 typedef enum {
     38     HWC2_ATTRIBUTE_INVALID = 0,
     39 
     40     /* Dimensions in pixels */
     41     HWC2_ATTRIBUTE_WIDTH = 1,
     42     HWC2_ATTRIBUTE_HEIGHT = 2,
     43 
     44     /* Vsync period in nanoseconds */
     45     HWC2_ATTRIBUTE_VSYNC_PERIOD = 3,
     46 
     47     /* Dots per thousand inches (DPI * 1000). Scaling by 1000 allows these
     48      * numbers to be stored in an int32_t without losing too much precision. If
     49      * the DPI for a configuration is unavailable or is considered unreliable,
     50      * the device may return -1 instead */
     51     HWC2_ATTRIBUTE_DPI_X = 4,
     52     HWC2_ATTRIBUTE_DPI_Y = 5,
     53 } hwc2_attribute_t;
     54 
     55 /* Blend modes, settable per layer */
     56 typedef enum {
     57     HWC2_BLEND_MODE_INVALID = 0,
     58 
     59     /* colorOut = colorSrc */
     60     HWC2_BLEND_MODE_NONE = 1,
     61 
     62     /* colorOut = colorSrc + colorDst * (1 - alphaSrc) */
     63     HWC2_BLEND_MODE_PREMULTIPLIED = 2,
     64 
     65     /* colorOut = colorSrc * alphaSrc + colorDst * (1 - alphaSrc) */
     66     HWC2_BLEND_MODE_COVERAGE = 3,
     67 } hwc2_blend_mode_t;
     68 
     69 /* See the 'Callbacks' section for more detailed descriptions of what these
     70  * functions do */
     71 typedef enum {
     72     HWC2_CALLBACK_INVALID = 0,
     73     HWC2_CALLBACK_HOTPLUG = 1,
     74     HWC2_CALLBACK_REFRESH = 2,
     75     HWC2_CALLBACK_VSYNC = 3,
     76 } hwc2_callback_descriptor_t;
     77 
     78 /* Optional capabilities which may be supported by some devices. The particular
     79  * set of supported capabilities for a given device may be retrieved using
     80  * getCapabilities. */
     81 typedef enum {
     82     HWC2_CAPABILITY_INVALID = 0,
     83 
     84     /* Specifies that the device supports sideband stream layers, for which
     85      * buffer content updates and other synchronization will not be provided
     86      * through the usual validate/present cycle and must be handled by an
     87      * external implementation-defined mechanism. Only changes to layer state
     88      * (such as position, size, etc.) need to be performed through the
     89      * validate/present cycle. */
     90     HWC2_CAPABILITY_SIDEBAND_STREAM = 1,
     91 
     92     /* Specifies that the device will apply a color transform even when either
     93      * the client or the device has chosen that all layers should be composed by
     94      * the client. This will prevent the client from applying the color
     95      * transform during its composition step. */
     96     HWC2_CAPABILITY_SKIP_CLIENT_COLOR_TRANSFORM = 2,
     97 
     98     /* Specifies that the present fence must not be used as an accurate
     99      * representation of the actual present time of a frame.
    100      * This capability must never be set by HWC2 devices.
    101      * This capability may be set for HWC1 devices that use the
    102      * HWC2On1Adapter where emulation of the present fence using the retire
    103      * fence is not feasible.
    104      * In the future, CTS tests will require present time to be reliable.
    105      */
    106     HWC2_CAPABILITY_PRESENT_FENCE_IS_NOT_RELIABLE = 3,
    107 
    108     /* Specifies that a device is able to skip the validateDisplay call before
    109      * receiving a call to presentDisplay. The client will always skip
    110      * validateDisplay and try to call presentDisplay regardless of the changes
    111      * in the properties of the layers. If the device returns anything else than
    112      * HWC2_ERROR_NONE, it will call validateDisplay then presentDisplay again.
    113      * For this capability to be worthwhile the device implementation of
    114      * presentDisplay should fail as fast as possible in the case a
    115      * validateDisplay step is needed.
    116      */
    117     HWC2_CAPABILITY_SKIP_VALIDATE = 4,
    118 } hwc2_capability_t;
    119 
    120 /* Possible composition types for a given layer */
    121 typedef enum {
    122     HWC2_COMPOSITION_INVALID = 0,
    123 
    124     /* The client will composite this layer into the client target buffer
    125      * (provided to the device through setClientTarget).
    126      *
    127      * The device must not request any composition type changes for layers of
    128      * this type. */
    129     HWC2_COMPOSITION_CLIENT = 1,
    130 
    131     /* The device will handle the composition of this layer through a hardware
    132      * overlay or other similar means.
    133      *
    134      * Upon validateDisplay, the device may request a change from this type to
    135      * HWC2_COMPOSITION_CLIENT. */
    136     HWC2_COMPOSITION_DEVICE = 2,
    137 
    138     /* The device will render this layer using the color set through
    139      * setLayerColor. If this functionality is not supported on a layer that the
    140      * client sets to HWC2_COMPOSITION_SOLID_COLOR, the device must request that
    141      * the composition type of that layer is changed to HWC2_COMPOSITION_CLIENT
    142      * upon the next call to validateDisplay.
    143      *
    144      * Upon validateDisplay, the device may request a change from this type to
    145      * HWC2_COMPOSITION_CLIENT. */
    146     HWC2_COMPOSITION_SOLID_COLOR = 3,
    147 
    148     /* Similar to DEVICE, but the position of this layer may also be set
    149      * asynchronously through setCursorPosition. If this functionality is not
    150      * supported on a layer that the client sets to HWC2_COMPOSITION_CURSOR, the
    151      * device must request that the composition type of that layer is changed to
    152      * HWC2_COMPOSITION_CLIENT upon the next call to validateDisplay.
    153      *
    154      * Upon validateDisplay, the device may request a change from this type to
    155      * either HWC2_COMPOSITION_DEVICE or HWC2_COMPOSITION_CLIENT. Changing to
    156      * HWC2_COMPOSITION_DEVICE will prevent the use of setCursorPosition but
    157      * still permit the device to composite the layer. */
    158     HWC2_COMPOSITION_CURSOR = 4,
    159 
    160     /* The device will handle the composition of this layer, as well as its
    161      * buffer updates and content synchronization. Only supported on devices
    162      * which provide HWC2_CAPABILITY_SIDEBAND_STREAM.
    163      *
    164      * Upon validateDisplay, the device may request a change from this type to
    165      * either HWC2_COMPOSITION_DEVICE or HWC2_COMPOSITION_CLIENT, but it is
    166      * unlikely that content will display correctly in these cases. */
    167     HWC2_COMPOSITION_SIDEBAND = 5,
    168 } hwc2_composition_t;
    169 
    170 /* Possible connection options from the hotplug callback */
    171 typedef enum {
    172     HWC2_CONNECTION_INVALID = 0,
    173 
    174     /* The display has been connected */
    175     HWC2_CONNECTION_CONNECTED = 1,
    176 
    177     /* The display has been disconnected */
    178     HWC2_CONNECTION_DISCONNECTED = 2,
    179 } hwc2_connection_t;
    180 
    181 /* Display requests returned by getDisplayRequests */
    182 typedef enum {
    183     /* Instructs the client to provide a new client target buffer, even if no
    184      * layers are marked for client composition. */
    185     HWC2_DISPLAY_REQUEST_FLIP_CLIENT_TARGET = 1 << 0,
    186 
    187     /* Instructs the client to write the result of client composition directly
    188      * into the virtual display output buffer. If any of the layers are not
    189      * marked as HWC2_COMPOSITION_CLIENT or the given display is not a virtual
    190      * display, this request has no effect. */
    191     HWC2_DISPLAY_REQUEST_WRITE_CLIENT_TARGET_TO_OUTPUT = 1 << 1,
    192 } hwc2_display_request_t;
    193 
    194 /* Display types returned by getDisplayType */
    195 typedef enum {
    196     HWC2_DISPLAY_TYPE_INVALID = 0,
    197 
    198     /* All physical displays, including both internal displays and hotpluggable
    199      * external displays */
    200     HWC2_DISPLAY_TYPE_PHYSICAL = 1,
    201 
    202     /* Virtual displays created by createVirtualDisplay */
    203     HWC2_DISPLAY_TYPE_VIRTUAL = 2,
    204 } hwc2_display_type_t;
    205 
    206 /* Return codes from all functions */
    207 typedef enum {
    208     HWC2_ERROR_NONE = 0,
    209     HWC2_ERROR_BAD_CONFIG,
    210     HWC2_ERROR_BAD_DISPLAY,
    211     HWC2_ERROR_BAD_LAYER,
    212     HWC2_ERROR_BAD_PARAMETER,
    213     HWC2_ERROR_HAS_CHANGES,
    214     HWC2_ERROR_NO_RESOURCES,
    215     HWC2_ERROR_NOT_VALIDATED,
    216     HWC2_ERROR_UNSUPPORTED,
    217 } hwc2_error_t;
    218 
    219 /* Function descriptors for use with getFunction */
    220 typedef enum {
    221     HWC2_FUNCTION_INVALID = 0,
    222     HWC2_FUNCTION_ACCEPT_DISPLAY_CHANGES,
    223     HWC2_FUNCTION_CREATE_LAYER,
    224     HWC2_FUNCTION_CREATE_VIRTUAL_DISPLAY,
    225     HWC2_FUNCTION_DESTROY_LAYER,
    226     HWC2_FUNCTION_DESTROY_VIRTUAL_DISPLAY,
    227     HWC2_FUNCTION_DUMP,
    228     HWC2_FUNCTION_GET_ACTIVE_CONFIG,
    229     HWC2_FUNCTION_GET_CHANGED_COMPOSITION_TYPES,
    230     HWC2_FUNCTION_GET_CLIENT_TARGET_SUPPORT,
    231     HWC2_FUNCTION_GET_COLOR_MODES,
    232     HWC2_FUNCTION_GET_DISPLAY_ATTRIBUTE,
    233     HWC2_FUNCTION_GET_DISPLAY_CONFIGS,
    234     HWC2_FUNCTION_GET_DISPLAY_NAME,
    235     HWC2_FUNCTION_GET_DISPLAY_REQUESTS,
    236     HWC2_FUNCTION_GET_DISPLAY_TYPE,
    237     HWC2_FUNCTION_GET_DOZE_SUPPORT,
    238     HWC2_FUNCTION_GET_HDR_CAPABILITIES,
    239     HWC2_FUNCTION_GET_MAX_VIRTUAL_DISPLAY_COUNT,
    240     HWC2_FUNCTION_GET_RELEASE_FENCES,
    241     HWC2_FUNCTION_PRESENT_DISPLAY,
    242     HWC2_FUNCTION_REGISTER_CALLBACK,
    243     HWC2_FUNCTION_SET_ACTIVE_CONFIG,
    244     HWC2_FUNCTION_SET_CLIENT_TARGET,
    245     HWC2_FUNCTION_SET_COLOR_MODE,
    246     HWC2_FUNCTION_SET_COLOR_TRANSFORM,
    247     HWC2_FUNCTION_SET_CURSOR_POSITION,
    248     HWC2_FUNCTION_SET_LAYER_BLEND_MODE,
    249     HWC2_FUNCTION_SET_LAYER_BUFFER,
    250     HWC2_FUNCTION_SET_LAYER_COLOR,
    251     HWC2_FUNCTION_SET_LAYER_COMPOSITION_TYPE,
    252     HWC2_FUNCTION_SET_LAYER_DATASPACE,
    253     HWC2_FUNCTION_SET_LAYER_DISPLAY_FRAME,
    254     HWC2_FUNCTION_SET_LAYER_PLANE_ALPHA,
    255     HWC2_FUNCTION_SET_LAYER_SIDEBAND_STREAM,
    256     HWC2_FUNCTION_SET_LAYER_SOURCE_CROP,
    257     HWC2_FUNCTION_SET_LAYER_SURFACE_DAMAGE,
    258     HWC2_FUNCTION_SET_LAYER_TRANSFORM,
    259     HWC2_FUNCTION_SET_LAYER_VISIBLE_REGION,
    260     HWC2_FUNCTION_SET_LAYER_Z_ORDER,
    261     HWC2_FUNCTION_SET_OUTPUT_BUFFER,
    262     HWC2_FUNCTION_SET_POWER_MODE,
    263     HWC2_FUNCTION_SET_VSYNC_ENABLED,
    264     HWC2_FUNCTION_VALIDATE_DISPLAY,
    265     HWC2_FUNCTION_SET_LAYER_FLOAT_COLOR,
    266     HWC2_FUNCTION_SET_LAYER_PER_FRAME_METADATA,
    267     HWC2_FUNCTION_GET_PER_FRAME_METADATA_KEYS,
    268     HWC2_FUNCTION_SET_READBACK_BUFFER,
    269     HWC2_FUNCTION_GET_READBACK_BUFFER_ATTRIBUTES,
    270     HWC2_FUNCTION_GET_READBACK_BUFFER_FENCE,
    271     HWC2_FUNCTION_GET_RENDER_INTENTS,
    272     HWC2_FUNCTION_SET_COLOR_MODE_WITH_RENDER_INTENT,
    273     HWC2_FUNCTION_GET_DATASPACE_SATURATION_MATRIX
    274 } hwc2_function_descriptor_t;
    275 
    276 /* Layer requests returned from getDisplayRequests */
    277 typedef enum {
    278     /* The client should clear its target with transparent pixels where this
    279      * layer would be. The client may ignore this request if the layer must be
    280      * blended. */
    281     HWC2_LAYER_REQUEST_CLEAR_CLIENT_TARGET = 1 << 0,
    282 } hwc2_layer_request_t;
    283 
    284 /* Power modes for use with setPowerMode */
    285 typedef enum {
    286     /* The display is fully off (blanked) */
    287     HWC2_POWER_MODE_OFF = 0,
    288 
    289     /* These are optional low power modes. getDozeSupport may be called to
    290      * determine whether a given display supports these modes. */
    291 
    292     /* The display is turned on and configured in a low power state that is
    293      * suitable for presenting ambient information to the user, possibly with
    294      * lower fidelity than HWC2_POWER_MODE_ON, but with greater efficiency. */
    295     HWC2_POWER_MODE_DOZE = 1,
    296 
    297     /* The display is configured as in HWC2_POWER_MODE_DOZE but may stop
    298      * applying display updates from the client. This is effectively a hint to
    299      * the device that drawing to the display has been suspended and that the
    300      * the device should remain on in a low power state and continue displaying
    301      * its current contents indefinitely until the power mode changes.
    302      *
    303      * This mode may also be used as a signal to enable hardware-based doze
    304      * functionality. In this case, the device is free to take over the display
    305      * and manage it autonomously to implement a low power always-on display. */
    306     HWC2_POWER_MODE_DOZE_SUSPEND = 3,
    307 
    308     /* The display is fully on */
    309     HWC2_POWER_MODE_ON = 2,
    310 } hwc2_power_mode_t;
    311 
    312 /* Vsync values passed to setVsyncEnabled */
    313 typedef enum {
    314     HWC2_VSYNC_INVALID = 0,
    315 
    316     /* Enable vsync */
    317     HWC2_VSYNC_ENABLE = 1,
    318 
    319     /* Disable vsync */
    320     HWC2_VSYNC_DISABLE = 2,
    321 } hwc2_vsync_t;
    322 
    323 /* MUST match HIDL's V2_2::IComposerClient::PerFrameMetadataKey */
    324 typedef enum {
    325     /* SMPTE ST 2084:2014.
    326      * Coordinates defined in CIE 1931 xy chromaticity space
    327      */
    328     HWC2_DISPLAY_RED_PRIMARY_X = 0,
    329     HWC2_DISPLAY_RED_PRIMARY_Y = 1,
    330     HWC2_DISPLAY_GREEN_PRIMARY_X = 2,
    331     HWC2_DISPLAY_GREEN_PRIMARY_Y = 3,
    332     HWC2_DISPLAY_BLUE_PRIMARY_X = 4,
    333     HWC2_DISPLAY_BLUE_PRIMARY_Y = 5,
    334     HWC2_WHITE_POINT_X = 6,
    335     HWC2_WHITE_POINT_Y = 7,
    336     /* SMPTE ST 2084:2014.
    337      * Units: nits
    338      * max as defined by ST 2048: 10,000 nits
    339      */
    340     HWC2_MAX_LUMINANCE = 8,
    341     HWC2_MIN_LUMINANCE = 9,
    342 
    343     /* CTA 861.3
    344      * Units: nits
    345      */
    346     HWC2_MAX_CONTENT_LIGHT_LEVEL = 10,
    347     HWC2_MAX_FRAME_AVERAGE_LIGHT_LEVEL = 11,
    348 } hwc2_per_frame_metadata_key_t;
    349 
    350 /*
    351  * Stringification Functions
    352  */
    353 
    354 #ifdef HWC2_INCLUDE_STRINGIFICATION
    355 
    356 static inline const char* getAttributeName(hwc2_attribute_t attribute) {
    357     switch (attribute) {
    358         case HWC2_ATTRIBUTE_INVALID: return "Invalid";
    359         case HWC2_ATTRIBUTE_WIDTH: return "Width";
    360         case HWC2_ATTRIBUTE_HEIGHT: return "Height";
    361         case HWC2_ATTRIBUTE_VSYNC_PERIOD: return "VsyncPeriod";
    362         case HWC2_ATTRIBUTE_DPI_X: return "DpiX";
    363         case HWC2_ATTRIBUTE_DPI_Y: return "DpiY";
    364         default: return "Unknown";
    365     }
    366 }
    367 
    368 static inline const char* getBlendModeName(hwc2_blend_mode_t mode) {
    369     switch (mode) {
    370         case HWC2_BLEND_MODE_INVALID: return "Invalid";
    371         case HWC2_BLEND_MODE_NONE: return "None";
    372         case HWC2_BLEND_MODE_PREMULTIPLIED: return "Premultiplied";
    373         case HWC2_BLEND_MODE_COVERAGE: return "Coverage";
    374         default: return "Unknown";
    375     }
    376 }
    377 
    378 static inline const char* getCallbackDescriptorName(
    379         hwc2_callback_descriptor_t desc) {
    380     switch (desc) {
    381         case HWC2_CALLBACK_INVALID: return "Invalid";
    382         case HWC2_CALLBACK_HOTPLUG: return "Hotplug";
    383         case HWC2_CALLBACK_REFRESH: return "Refresh";
    384         case HWC2_CALLBACK_VSYNC: return "Vsync";
    385         default: return "Unknown";
    386     }
    387 }
    388 
    389 static inline const char* getCapabilityName(hwc2_capability_t capability) {
    390     switch (capability) {
    391         case HWC2_CAPABILITY_INVALID: return "Invalid";
    392         case HWC2_CAPABILITY_SIDEBAND_STREAM: return "SidebandStream";
    393         case HWC2_CAPABILITY_SKIP_CLIENT_COLOR_TRANSFORM:
    394                 return "SkipClientColorTransform";
    395         case HWC2_CAPABILITY_PRESENT_FENCE_IS_NOT_RELIABLE:
    396                 return "PresentFenceIsNotReliable";
    397         default: return "Unknown";
    398     }
    399 }
    400 
    401 static inline const char* getCompositionName(hwc2_composition_t composition) {
    402     switch (composition) {
    403         case HWC2_COMPOSITION_INVALID: return "Invalid";
    404         case HWC2_COMPOSITION_CLIENT: return "Client";
    405         case HWC2_COMPOSITION_DEVICE: return "Device";
    406         case HWC2_COMPOSITION_SOLID_COLOR: return "SolidColor";
    407         case HWC2_COMPOSITION_CURSOR: return "Cursor";
    408         case HWC2_COMPOSITION_SIDEBAND: return "Sideband";
    409         default: return "Unknown";
    410     }
    411 }
    412 
    413 static inline const char* getConnectionName(hwc2_connection_t connection) {
    414     switch (connection) {
    415         case HWC2_CONNECTION_INVALID: return "Invalid";
    416         case HWC2_CONNECTION_CONNECTED: return "Connected";
    417         case HWC2_CONNECTION_DISCONNECTED: return "Disconnected";
    418         default: return "Unknown";
    419     }
    420 }
    421 
    422 static inline const char* getDisplayRequestName(
    423         hwc2_display_request_t request) {
    424     switch (__BIONIC_CAST(static_cast, int, request)) {
    425         case 0: return "None";
    426         case HWC2_DISPLAY_REQUEST_FLIP_CLIENT_TARGET: return "FlipClientTarget";
    427         case HWC2_DISPLAY_REQUEST_WRITE_CLIENT_TARGET_TO_OUTPUT:
    428             return "WriteClientTargetToOutput";
    429         case HWC2_DISPLAY_REQUEST_FLIP_CLIENT_TARGET |
    430                 HWC2_DISPLAY_REQUEST_WRITE_CLIENT_TARGET_TO_OUTPUT:
    431             return "FlipClientTarget|WriteClientTargetToOutput";
    432         default: return "Unknown";
    433     }
    434 }
    435 
    436 static inline const char* getDisplayTypeName(hwc2_display_type_t type) {
    437     switch (type) {
    438         case HWC2_DISPLAY_TYPE_INVALID: return "Invalid";
    439         case HWC2_DISPLAY_TYPE_PHYSICAL: return "Physical";
    440         case HWC2_DISPLAY_TYPE_VIRTUAL: return "Virtual";
    441         default: return "Unknown";
    442     }
    443 }
    444 
    445 static inline const char* getErrorName(hwc2_error_t error) {
    446     switch (error) {
    447         case HWC2_ERROR_NONE: return "None";
    448         case HWC2_ERROR_BAD_CONFIG: return "BadConfig";
    449         case HWC2_ERROR_BAD_DISPLAY: return "BadDisplay";
    450         case HWC2_ERROR_BAD_LAYER: return "BadLayer";
    451         case HWC2_ERROR_BAD_PARAMETER: return "BadParameter";
    452         case HWC2_ERROR_HAS_CHANGES: return "HasChanges";
    453         case HWC2_ERROR_NO_RESOURCES: return "NoResources";
    454         case HWC2_ERROR_NOT_VALIDATED: return "NotValidated";
    455         case HWC2_ERROR_UNSUPPORTED: return "Unsupported";
    456         default: return "Unknown";
    457     }
    458 }
    459 
    460 static inline const char* getFunctionDescriptorName(
    461         hwc2_function_descriptor_t desc) {
    462     switch (desc) {
    463         case HWC2_FUNCTION_INVALID: return "Invalid";
    464         case HWC2_FUNCTION_ACCEPT_DISPLAY_CHANGES:
    465             return "AcceptDisplayChanges";
    466         case HWC2_FUNCTION_CREATE_LAYER: return "CreateLayer";
    467         case HWC2_FUNCTION_CREATE_VIRTUAL_DISPLAY:
    468             return "CreateVirtualDisplay";
    469         case HWC2_FUNCTION_DESTROY_LAYER: return "DestroyLayer";
    470         case HWC2_FUNCTION_DESTROY_VIRTUAL_DISPLAY:
    471             return "DestroyVirtualDisplay";
    472         case HWC2_FUNCTION_DUMP: return "Dump";
    473         case HWC2_FUNCTION_GET_ACTIVE_CONFIG: return "GetActiveConfig";
    474         case HWC2_FUNCTION_GET_CHANGED_COMPOSITION_TYPES:
    475             return "GetChangedCompositionTypes";
    476         case HWC2_FUNCTION_GET_CLIENT_TARGET_SUPPORT:
    477             return "GetClientTargetSupport";
    478         case HWC2_FUNCTION_GET_COLOR_MODES: return "GetColorModes";
    479         case HWC2_FUNCTION_GET_DISPLAY_ATTRIBUTE: return "GetDisplayAttribute";
    480         case HWC2_FUNCTION_GET_DISPLAY_CONFIGS: return "GetDisplayConfigs";
    481         case HWC2_FUNCTION_GET_DISPLAY_NAME: return "GetDisplayName";
    482         case HWC2_FUNCTION_GET_DISPLAY_REQUESTS: return "GetDisplayRequests";
    483         case HWC2_FUNCTION_GET_DISPLAY_TYPE: return "GetDisplayType";
    484         case HWC2_FUNCTION_GET_DOZE_SUPPORT: return "GetDozeSupport";
    485         case HWC2_FUNCTION_GET_HDR_CAPABILITIES: return "GetHdrCapabilities";
    486         case HWC2_FUNCTION_GET_MAX_VIRTUAL_DISPLAY_COUNT:
    487             return "GetMaxVirtualDisplayCount";
    488         case HWC2_FUNCTION_GET_RELEASE_FENCES: return "GetReleaseFences";
    489         case HWC2_FUNCTION_PRESENT_DISPLAY: return "PresentDisplay";
    490         case HWC2_FUNCTION_REGISTER_CALLBACK: return "RegisterCallback";
    491         case HWC2_FUNCTION_SET_ACTIVE_CONFIG: return "SetActiveConfig";
    492         case HWC2_FUNCTION_SET_CLIENT_TARGET: return "SetClientTarget";
    493         case HWC2_FUNCTION_SET_COLOR_MODE: return "SetColorMode";
    494         case HWC2_FUNCTION_SET_COLOR_TRANSFORM: return "SetColorTransform";
    495         case HWC2_FUNCTION_SET_CURSOR_POSITION: return "SetCursorPosition";
    496         case HWC2_FUNCTION_SET_LAYER_BLEND_MODE: return "SetLayerBlendMode";
    497         case HWC2_FUNCTION_SET_LAYER_BUFFER: return "SetLayerBuffer";
    498         case HWC2_FUNCTION_SET_LAYER_COLOR: return "SetLayerColor";
    499         case HWC2_FUNCTION_SET_LAYER_COMPOSITION_TYPE:
    500             return "SetLayerCompositionType";
    501         case HWC2_FUNCTION_SET_LAYER_DATASPACE: return "SetLayerDataspace";
    502         case HWC2_FUNCTION_SET_LAYER_DISPLAY_FRAME:
    503             return "SetLayerDisplayFrame";
    504         case HWC2_FUNCTION_SET_LAYER_PLANE_ALPHA: return "SetLayerPlaneAlpha";
    505         case HWC2_FUNCTION_SET_LAYER_SIDEBAND_STREAM:
    506             return "SetLayerSidebandStream";
    507         case HWC2_FUNCTION_SET_LAYER_SOURCE_CROP: return "SetLayerSourceCrop";
    508         case HWC2_FUNCTION_SET_LAYER_SURFACE_DAMAGE:
    509             return "SetLayerSurfaceDamage";
    510         case HWC2_FUNCTION_SET_LAYER_TRANSFORM: return "SetLayerTransform";
    511         case HWC2_FUNCTION_SET_LAYER_VISIBLE_REGION:
    512             return "SetLayerVisibleRegion";
    513         case HWC2_FUNCTION_SET_LAYER_Z_ORDER: return "SetLayerZOrder";
    514         case HWC2_FUNCTION_SET_OUTPUT_BUFFER: return "SetOutputBuffer";
    515         case HWC2_FUNCTION_SET_POWER_MODE: return "SetPowerMode";
    516         case HWC2_FUNCTION_SET_VSYNC_ENABLED: return "SetVsyncEnabled";
    517         case HWC2_FUNCTION_VALIDATE_DISPLAY: return "ValidateDisplay";
    518         case HWC2_FUNCTION_SET_LAYER_FLOAT_COLOR: return "SetLayerFloatColor";
    519         case HWC2_FUNCTION_SET_LAYER_PER_FRAME_METADATA: return "SetLayerPerFrameMetadata";
    520         case HWC2_FUNCTION_GET_PER_FRAME_METADATA_KEYS: return "GetPerFrameMetadataKeys";
    521         case HWC2_FUNCTION_SET_READBACK_BUFFER: return "SetReadbackBuffer";
    522         case HWC2_FUNCTION_GET_READBACK_BUFFER_ATTRIBUTES: return "GetReadbackBufferAttributes";
    523         case HWC2_FUNCTION_GET_READBACK_BUFFER_FENCE: return "GetReadbackBufferFence";
    524         case HWC2_FUNCTION_GET_RENDER_INTENTS: return "GetRenderIntents";
    525         case HWC2_FUNCTION_SET_COLOR_MODE_WITH_RENDER_INTENT: return "SetColorModeWithRenderIntent";
    526         case HWC2_FUNCTION_GET_DATASPACE_SATURATION_MATRIX: return "GetDataspaceSaturationMatrix";
    527         default: return "Unknown";
    528     }
    529 }
    530 
    531 static inline const char* getLayerRequestName(hwc2_layer_request_t request) {
    532     switch (__BIONIC_CAST(static_cast, int, request)) {
    533         case 0: return "None";
    534         case HWC2_LAYER_REQUEST_CLEAR_CLIENT_TARGET: return "ClearClientTarget";
    535         default: return "Unknown";
    536     }
    537 }
    538 
    539 static inline const char* getPowerModeName(hwc2_power_mode_t mode) {
    540     switch (mode) {
    541         case HWC2_POWER_MODE_OFF: return "Off";
    542         case HWC2_POWER_MODE_DOZE_SUSPEND: return "DozeSuspend";
    543         case HWC2_POWER_MODE_DOZE: return "Doze";
    544         case HWC2_POWER_MODE_ON: return "On";
    545         default: return "Unknown";
    546     }
    547 }
    548 
    549 static inline const char* getTransformName(hwc_transform_t transform) {
    550     switch (__BIONIC_CAST(static_cast, int, transform)) {
    551         case 0: return "None";
    552         case HWC_TRANSFORM_FLIP_H: return "FlipH";
    553         case HWC_TRANSFORM_FLIP_V: return "FlipV";
    554         case HWC_TRANSFORM_ROT_90: return "Rotate90";
    555         case HWC_TRANSFORM_ROT_180: return "Rotate180";
    556         case HWC_TRANSFORM_ROT_270: return "Rotate270";
    557         case HWC_TRANSFORM_FLIP_H_ROT_90: return "FlipHRotate90";
    558         case HWC_TRANSFORM_FLIP_V_ROT_90: return "FlipVRotate90";
    559         default: return "Unknown";
    560     }
    561 }
    562 
    563 static inline const char* getVsyncName(hwc2_vsync_t vsync) {
    564     switch (vsync) {
    565         case HWC2_VSYNC_INVALID: return "Invalid";
    566         case HWC2_VSYNC_ENABLE: return "Enable";
    567         case HWC2_VSYNC_DISABLE: return "Disable";
    568         default: return "Unknown";
    569     }
    570 }
    571 
    572 #define TO_STRING(E, T, printer) \
    573     inline std::string to_string(E value) { return printer(value); } \
    574     inline std::string to_string(T value) { return to_string(static_cast<E>(value)); }
    575 #else // !HWC2_INCLUDE_STRINGIFICATION
    576 #define TO_STRING(name, printer)
    577 #endif // HWC2_INCLUDE_STRINGIFICATION
    578 
    579 /*
    580  * C++11 features
    581  */
    582 
    583 #ifdef HWC2_USE_CPP11
    584 __END_DECLS
    585 
    586 #ifdef HWC2_INCLUDE_STRINGIFICATION
    587 #include <string>
    588 #endif
    589 
    590 namespace HWC2 {
    591 
    592 enum class Attribute : int32_t {
    593     Invalid = HWC2_ATTRIBUTE_INVALID,
    594     Width = HWC2_ATTRIBUTE_WIDTH,
    595     Height = HWC2_ATTRIBUTE_HEIGHT,
    596     VsyncPeriod = HWC2_ATTRIBUTE_VSYNC_PERIOD,
    597     DpiX = HWC2_ATTRIBUTE_DPI_X,
    598     DpiY = HWC2_ATTRIBUTE_DPI_Y,
    599 };
    600 TO_STRING(hwc2_attribute_t, Attribute, getAttributeName)
    601 
    602 enum class BlendMode : int32_t {
    603     Invalid = HWC2_BLEND_MODE_INVALID,
    604     None = HWC2_BLEND_MODE_NONE,
    605     Premultiplied = HWC2_BLEND_MODE_PREMULTIPLIED,
    606     Coverage = HWC2_BLEND_MODE_COVERAGE,
    607 };
    608 TO_STRING(hwc2_blend_mode_t, BlendMode, getBlendModeName)
    609 
    610 enum class Callback : int32_t {
    611     Invalid = HWC2_CALLBACK_INVALID,
    612     Hotplug = HWC2_CALLBACK_HOTPLUG,
    613     Refresh = HWC2_CALLBACK_REFRESH,
    614     Vsync = HWC2_CALLBACK_VSYNC,
    615 };
    616 TO_STRING(hwc2_callback_descriptor_t, Callback, getCallbackDescriptorName)
    617 
    618 enum class Capability : int32_t {
    619     Invalid = HWC2_CAPABILITY_INVALID,
    620     SidebandStream = HWC2_CAPABILITY_SIDEBAND_STREAM,
    621     SkipClientColorTransform = HWC2_CAPABILITY_SKIP_CLIENT_COLOR_TRANSFORM,
    622     PresentFenceIsNotReliable = HWC2_CAPABILITY_PRESENT_FENCE_IS_NOT_RELIABLE,
    623     SkipValidate = HWC2_CAPABILITY_SKIP_VALIDATE,
    624 };
    625 TO_STRING(hwc2_capability_t, Capability, getCapabilityName)
    626 
    627 enum class Composition : int32_t {
    628     Invalid = HWC2_COMPOSITION_INVALID,
    629     Client = HWC2_COMPOSITION_CLIENT,
    630     Device = HWC2_COMPOSITION_DEVICE,
    631     SolidColor = HWC2_COMPOSITION_SOLID_COLOR,
    632     Cursor = HWC2_COMPOSITION_CURSOR,
    633     Sideband = HWC2_COMPOSITION_SIDEBAND,
    634 };
    635 TO_STRING(hwc2_composition_t, Composition, getCompositionName)
    636 
    637 enum class Connection : int32_t {
    638     Invalid = HWC2_CONNECTION_INVALID,
    639     Connected = HWC2_CONNECTION_CONNECTED,
    640     Disconnected = HWC2_CONNECTION_DISCONNECTED,
    641 };
    642 TO_STRING(hwc2_connection_t, Connection, getConnectionName)
    643 
    644 enum class DisplayRequest : int32_t {
    645     FlipClientTarget = HWC2_DISPLAY_REQUEST_FLIP_CLIENT_TARGET,
    646     WriteClientTargetToOutput =
    647         HWC2_DISPLAY_REQUEST_WRITE_CLIENT_TARGET_TO_OUTPUT,
    648 };
    649 TO_STRING(hwc2_display_request_t, DisplayRequest, getDisplayRequestName)
    650 
    651 enum class DisplayType : int32_t {
    652     Invalid = HWC2_DISPLAY_TYPE_INVALID,
    653     Physical = HWC2_DISPLAY_TYPE_PHYSICAL,
    654     Virtual = HWC2_DISPLAY_TYPE_VIRTUAL,
    655 };
    656 TO_STRING(hwc2_display_type_t, DisplayType, getDisplayTypeName)
    657 
    658 enum class Error : int32_t {
    659     None = HWC2_ERROR_NONE,
    660     BadConfig = HWC2_ERROR_BAD_CONFIG,
    661     BadDisplay = HWC2_ERROR_BAD_DISPLAY,
    662     BadLayer = HWC2_ERROR_BAD_LAYER,
    663     BadParameter = HWC2_ERROR_BAD_PARAMETER,
    664     HasChanges = HWC2_ERROR_HAS_CHANGES,
    665     NoResources = HWC2_ERROR_NO_RESOURCES,
    666     NotValidated = HWC2_ERROR_NOT_VALIDATED,
    667     Unsupported = HWC2_ERROR_UNSUPPORTED,
    668 };
    669 TO_STRING(hwc2_error_t, Error, getErrorName)
    670 
    671 enum class FunctionDescriptor : int32_t {
    672     Invalid = HWC2_FUNCTION_INVALID,
    673     AcceptDisplayChanges = HWC2_FUNCTION_ACCEPT_DISPLAY_CHANGES,
    674     CreateLayer = HWC2_FUNCTION_CREATE_LAYER,
    675     CreateVirtualDisplay = HWC2_FUNCTION_CREATE_VIRTUAL_DISPLAY,
    676     DestroyLayer = HWC2_FUNCTION_DESTROY_LAYER,
    677     DestroyVirtualDisplay = HWC2_FUNCTION_DESTROY_VIRTUAL_DISPLAY,
    678     Dump = HWC2_FUNCTION_DUMP,
    679     GetActiveConfig = HWC2_FUNCTION_GET_ACTIVE_CONFIG,
    680     GetChangedCompositionTypes = HWC2_FUNCTION_GET_CHANGED_COMPOSITION_TYPES,
    681     GetClientTargetSupport = HWC2_FUNCTION_GET_CLIENT_TARGET_SUPPORT,
    682     GetColorModes = HWC2_FUNCTION_GET_COLOR_MODES,
    683     GetDisplayAttribute = HWC2_FUNCTION_GET_DISPLAY_ATTRIBUTE,
    684     GetDisplayConfigs = HWC2_FUNCTION_GET_DISPLAY_CONFIGS,
    685     GetDisplayName = HWC2_FUNCTION_GET_DISPLAY_NAME,
    686     GetDisplayRequests = HWC2_FUNCTION_GET_DISPLAY_REQUESTS,
    687     GetDisplayType = HWC2_FUNCTION_GET_DISPLAY_TYPE,
    688     GetDozeSupport = HWC2_FUNCTION_GET_DOZE_SUPPORT,
    689     GetHdrCapabilities = HWC2_FUNCTION_GET_HDR_CAPABILITIES,
    690     GetMaxVirtualDisplayCount = HWC2_FUNCTION_GET_MAX_VIRTUAL_DISPLAY_COUNT,
    691     GetReleaseFences = HWC2_FUNCTION_GET_RELEASE_FENCES,
    692     PresentDisplay = HWC2_FUNCTION_PRESENT_DISPLAY,
    693     RegisterCallback = HWC2_FUNCTION_REGISTER_CALLBACK,
    694     SetActiveConfig = HWC2_FUNCTION_SET_ACTIVE_CONFIG,
    695     SetClientTarget = HWC2_FUNCTION_SET_CLIENT_TARGET,
    696     SetColorMode = HWC2_FUNCTION_SET_COLOR_MODE,
    697     SetColorTransform = HWC2_FUNCTION_SET_COLOR_TRANSFORM,
    698     SetCursorPosition = HWC2_FUNCTION_SET_CURSOR_POSITION,
    699     SetLayerBlendMode = HWC2_FUNCTION_SET_LAYER_BLEND_MODE,
    700     SetLayerBuffer = HWC2_FUNCTION_SET_LAYER_BUFFER,
    701     SetLayerColor = HWC2_FUNCTION_SET_LAYER_COLOR,
    702     SetLayerCompositionType = HWC2_FUNCTION_SET_LAYER_COMPOSITION_TYPE,
    703     SetLayerDataspace = HWC2_FUNCTION_SET_LAYER_DATASPACE,
    704     SetLayerDisplayFrame = HWC2_FUNCTION_SET_LAYER_DISPLAY_FRAME,
    705     SetLayerPlaneAlpha = HWC2_FUNCTION_SET_LAYER_PLANE_ALPHA,
    706     SetLayerSidebandStream = HWC2_FUNCTION_SET_LAYER_SIDEBAND_STREAM,
    707     SetLayerSourceCrop = HWC2_FUNCTION_SET_LAYER_SOURCE_CROP,
    708     SetLayerSurfaceDamage = HWC2_FUNCTION_SET_LAYER_SURFACE_DAMAGE,
    709     SetLayerTransform = HWC2_FUNCTION_SET_LAYER_TRANSFORM,
    710     SetLayerVisibleRegion = HWC2_FUNCTION_SET_LAYER_VISIBLE_REGION,
    711     SetLayerZOrder = HWC2_FUNCTION_SET_LAYER_Z_ORDER,
    712     SetOutputBuffer = HWC2_FUNCTION_SET_OUTPUT_BUFFER,
    713     SetPowerMode = HWC2_FUNCTION_SET_POWER_MODE,
    714     SetVsyncEnabled = HWC2_FUNCTION_SET_VSYNC_ENABLED,
    715     ValidateDisplay = HWC2_FUNCTION_VALIDATE_DISPLAY,
    716     SetLayerFloatColor = HWC2_FUNCTION_SET_LAYER_FLOAT_COLOR,
    717     SetLayerPerFrameMetadata = HWC2_FUNCTION_SET_LAYER_PER_FRAME_METADATA,
    718     GetPerFrameMetadataKeys = HWC2_FUNCTION_GET_PER_FRAME_METADATA_KEYS,
    719     SetReadbackBuffer = HWC2_FUNCTION_SET_READBACK_BUFFER,
    720     GetReadbackBufferAttributes = HWC2_FUNCTION_GET_READBACK_BUFFER_ATTRIBUTES,
    721     GetReadbackBufferFence = HWC2_FUNCTION_GET_READBACK_BUFFER_FENCE,
    722     GetRenderIntents = HWC2_FUNCTION_GET_RENDER_INTENTS,
    723     SetColorModeWithRenderIntent = HWC2_FUNCTION_SET_COLOR_MODE_WITH_RENDER_INTENT,
    724     GetDataspaceSaturationMatrix = HWC2_FUNCTION_GET_DATASPACE_SATURATION_MATRIX,
    725 };
    726 TO_STRING(hwc2_function_descriptor_t, FunctionDescriptor,
    727         getFunctionDescriptorName)
    728 
    729 enum class LayerRequest : int32_t {
    730     ClearClientTarget = HWC2_LAYER_REQUEST_CLEAR_CLIENT_TARGET,
    731 };
    732 TO_STRING(hwc2_layer_request_t, LayerRequest, getLayerRequestName)
    733 
    734 enum class PowerMode : int32_t {
    735     Off = HWC2_POWER_MODE_OFF,
    736     DozeSuspend = HWC2_POWER_MODE_DOZE_SUSPEND,
    737     Doze = HWC2_POWER_MODE_DOZE,
    738     On = HWC2_POWER_MODE_ON,
    739 };
    740 TO_STRING(hwc2_power_mode_t, PowerMode, getPowerModeName)
    741 
    742 enum class Transform : int32_t {
    743     None = 0,
    744     FlipH = HWC_TRANSFORM_FLIP_H,
    745     FlipV = HWC_TRANSFORM_FLIP_V,
    746     Rotate90 = HWC_TRANSFORM_ROT_90,
    747     Rotate180 = HWC_TRANSFORM_ROT_180,
    748     Rotate270 = HWC_TRANSFORM_ROT_270,
    749     FlipHRotate90 = HWC_TRANSFORM_FLIP_H_ROT_90,
    750     FlipVRotate90 = HWC_TRANSFORM_FLIP_V_ROT_90,
    751 };
    752 TO_STRING(hwc_transform_t, Transform, getTransformName)
    753 
    754 enum class Vsync : int32_t {
    755     Invalid = HWC2_VSYNC_INVALID,
    756     Enable = HWC2_VSYNC_ENABLE,
    757     Disable = HWC2_VSYNC_DISABLE,
    758 };
    759 TO_STRING(hwc2_vsync_t, Vsync, getVsyncName)
    760 
    761 } // namespace HWC2
    762 
    763 __BEGIN_DECLS
    764 #endif // HWC2_USE_CPP11
    765 
    766 /*
    767  * Typedefs
    768  */
    769 
    770 typedef void (*hwc2_function_pointer_t)();
    771 
    772 typedef void* hwc2_callback_data_t;
    773 typedef uint32_t hwc2_config_t;
    774 typedef uint64_t hwc2_display_t;
    775 typedef uint64_t hwc2_layer_t;
    776 
    777 /*
    778  * Device Struct
    779  */
    780 
    781 typedef struct hwc2_device {
    782     /* Must be the first member of this struct, since a pointer to this struct
    783      * will be generated by casting from a hw_device_t* */
    784     struct hw_device_t common;
    785 
    786     /* getCapabilities(..., outCount, outCapabilities)
    787      *
    788      * Provides a list of capabilities (described in the definition of
    789      * hwc2_capability_t above) supported by this device. This list must
    790      * not change after the device has been loaded.
    791      *
    792      * Parameters:
    793      *   outCount - if outCapabilities was NULL, the number of capabilities
    794      *       which would have been returned; if outCapabilities was not NULL,
    795      *       the number of capabilities returned, which must not exceed the
    796      *       value stored in outCount prior to the call
    797      *   outCapabilities - a list of capabilities supported by this device; may
    798      *       be NULL, in which case this function must write into outCount the
    799      *       number of capabilities which would have been written into
    800      *       outCapabilities
    801      */
    802     void (*getCapabilities)(struct hwc2_device* device, uint32_t* outCount,
    803             int32_t* /*hwc2_capability_t*/ outCapabilities);
    804 
    805     /* getFunction(..., descriptor)
    806      *
    807      * Returns a function pointer which implements the requested description.
    808      *
    809      * Parameters:
    810      *   descriptor - the function to return
    811      *
    812      * Returns either a function pointer implementing the requested descriptor
    813      *   or NULL if the described function is not supported by this device.
    814      */
    815     hwc2_function_pointer_t (*getFunction)(struct hwc2_device* device,
    816             int32_t /*hwc2_function_descriptor_t*/ descriptor);
    817 } hwc2_device_t;
    818 
    819 static inline int hwc2_open(const struct hw_module_t* module,
    820         hwc2_device_t** device) {
    821     return module->methods->open(module, HWC_HARDWARE_COMPOSER,
    822             TO_HW_DEVICE_T_OPEN(device));
    823 }
    824 
    825 static inline int hwc2_close(hwc2_device_t* device) {
    826     return device->common.close(&device->common);
    827 }
    828 
    829 /*
    830  * Callbacks
    831  *
    832  * All of these callbacks take as their first parameter the callbackData which
    833  * was provided at the time of callback registration, so this parameter is
    834  * omitted from the described parameter lists.
    835  */
    836 
    837 /* hotplug(..., display, connected)
    838  * Descriptor: HWC2_CALLBACK_HOTPLUG
    839  * Will be provided to all HWC2 devices
    840  *
    841  * Notifies the client that the given display has either been connected or
    842  * disconnected. Every active display (even a built-in physical display) must
    843  * trigger at least one hotplug notification, even if it only occurs immediately
    844  * after callback registration.
    845  *
    846  * The client may call back into the device on the same thread to query display
    847  * properties (such as width, height, and vsync period), and other threads may
    848  * call into the device while the callback is in progress. The device must
    849  * serialize calls to this callback such that only one thread is calling it at a
    850  * time.
    851  *
    852  * Displays which have been connected are assumed to be in HWC2_POWER_MODE_OFF,
    853  * and the vsync callback should not be called for a display until vsync has
    854  * been enabled with setVsyncEnabled.
    855  *
    856  * Parameters:
    857  *   display - the display which has been hotplugged
    858  *   connected - whether the display has been connected or disconnected
    859  */
    860 typedef void (*HWC2_PFN_HOTPLUG)(hwc2_callback_data_t callbackData,
    861         hwc2_display_t display, int32_t /*hwc2_connection_t*/ connected);
    862 
    863 /* refresh(..., display)
    864  * Descriptor: HWC2_CALLBACK_REFRESH
    865  * Will be provided to all HWC2 devices
    866  *
    867  * Notifies the client to trigger a screen refresh. This forces all layer state
    868  * for this display to be resent, and the display to be validated and presented,
    869  * even if there have been no changes.
    870  *
    871  * This refresh will occur some time after the callback is initiated, but not
    872  * necessarily before it returns. This thread, however, is guaranteed not to
    873  * call back into the device, thus it is safe to trigger this callback from
    874  * other functions which call into the device.
    875  *
    876  * Parameters:
    877  *   display - the display to refresh
    878  */
    879 typedef void (*HWC2_PFN_REFRESH)(hwc2_callback_data_t callbackData,
    880         hwc2_display_t display);
    881 
    882 /* vsync(..., display, timestamp)
    883  * Descriptor: HWC2_CALLBACK_VSYNC
    884  * Will be provided to all HWC2 devices
    885  *
    886  * Notifies the client that a vsync event has occurred. This callback must
    887  * only be triggered when vsync is enabled for this display (through
    888  * setVsyncEnabled).
    889  *
    890  * This callback should be triggered from a thread of at least
    891  * HAL_PRIORITY_URGENT_DISPLAY with as little latency as possible, typically
    892  * less than 0.5 ms. This thread is guaranteed not to call back into the device.
    893  *
    894  * Parameters:
    895  *   display - the display which has received a vsync event
    896  *   timestamp - the CLOCK_MONOTONIC time at which the vsync event occurred, in
    897  *       nanoseconds
    898  */
    899 typedef void (*HWC2_PFN_VSYNC)(hwc2_callback_data_t callbackData,
    900         hwc2_display_t display, int64_t timestamp);
    901 
    902 /*
    903  * Device Functions
    904  *
    905  * All of these functions take as their first parameter a device pointer, so
    906  * this parameter is omitted from the described parameter lists.
    907  */
    908 
    909 /* createVirtualDisplay(..., width, height, format, outDisplay)
    910  * Descriptor: HWC2_FUNCTION_CREATE_VIRTUAL_DISPLAY
    911  * Must be provided by all HWC2 devices
    912  *
    913  * Creates a new virtual display with the given width and height. The format
    914  * passed into this function is the default format requested by the consumer of
    915  * the virtual display output buffers. If a different format will be returned by
    916  * the device, it should be returned in this parameter so it can be set properly
    917  * when handing the buffers to the consumer.
    918  *
    919  * The display will be assumed to be on from the time the first frame is
    920  * presented until the display is destroyed.
    921  *
    922  * Parameters:
    923  *   width - width in pixels
    924  *   height - height in pixels
    925  *   format - prior to the call, the default output buffer format selected by
    926  *       the consumer; after the call, the format the device will produce
    927  *   outDisplay - the newly-created virtual display; pointer will be non-NULL
    928  *
    929  * Returns HWC2_ERROR_NONE or one of the following errors:
    930  *   HWC2_ERROR_UNSUPPORTED - the width or height is too large for the device to
    931  *       be able to create a virtual display
    932  *   HWC2_ERROR_NO_RESOURCES - the device is unable to create a new virtual
    933  *       display at this time
    934  */
    935 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_CREATE_VIRTUAL_DISPLAY)(
    936         hwc2_device_t* device, uint32_t width, uint32_t height,
    937         int32_t* /*android_pixel_format_t*/ format, hwc2_display_t* outDisplay);
    938 
    939 /* destroyVirtualDisplay(..., display)
    940  * Descriptor: HWC2_FUNCTION_DESTROY_VIRTUAL_DISPLAY
    941  * Must be provided by all HWC2 devices
    942  *
    943  * Destroys a virtual display. After this call all resources consumed by this
    944  * display may be freed by the device and any operations performed on this
    945  * display should fail.
    946  *
    947  * Parameters:
    948  *   display - the virtual display to destroy
    949  *
    950  * Returns HWC2_ERROR_NONE or one of the following errors:
    951  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
    952  *   HWC2_ERROR_BAD_PARAMETER - the display handle which was passed in does not
    953  *       refer to a virtual display
    954  */
    955 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_DESTROY_VIRTUAL_DISPLAY)(
    956         hwc2_device_t* device, hwc2_display_t display);
    957 
    958 /* dump(..., outSize, outBuffer)
    959  * Descriptor: HWC2_FUNCTION_DUMP
    960  * Must be provided by all HWC2 devices
    961  *
    962  * Retrieves implementation-defined debug information, which will be displayed
    963  * during, for example, `dumpsys SurfaceFlinger`.
    964  *
    965  * If called with outBuffer == NULL, the device should store a copy of the
    966  * desired output and return its length in bytes in outSize. If the device
    967  * already has a stored copy, that copy should be purged and replaced with a
    968  * fresh copy.
    969  *
    970  * If called with outBuffer != NULL, the device should copy its stored version
    971  * of the output into outBuffer and store how many bytes of data it copied into
    972  * outSize. Prior to this call, the client will have populated outSize with the
    973  * maximum number of bytes outBuffer can hold. The device must not write more
    974  * than this amount into outBuffer. If the device does not currently have a
    975  * stored copy, then it should return 0 in outSize.
    976  *
    977  * Any data written into outBuffer need not be null-terminated.
    978  *
    979  * Parameters:
    980  *   outSize - if outBuffer was NULL, the number of bytes needed to copy the
    981  *       device's stored output; if outBuffer was not NULL, the number of bytes
    982  *       written into it, which must not exceed the value stored in outSize
    983  *       prior to the call; pointer will be non-NULL
    984  *   outBuffer - the buffer to write the dump output into; may be NULL as
    985  *       described above; data written into this buffer need not be
    986  *       null-terminated
    987  */
    988 typedef void (*HWC2_PFN_DUMP)(hwc2_device_t* device, uint32_t* outSize,
    989         char* outBuffer);
    990 
    991 /* getMaxVirtualDisplayCount(...)
    992  * Descriptor: HWC2_FUNCTION_GET_MAX_VIRTUAL_DISPLAY_COUNT
    993  * Must be provided by all HWC2 devices
    994  *
    995  * Returns the maximum number of virtual displays supported by this device
    996  * (which may be 0). The client will not attempt to create more than this many
    997  * virtual displays on this device. This number must not change for the lifetime
    998  * of the device.
    999  */
   1000 typedef uint32_t (*HWC2_PFN_GET_MAX_VIRTUAL_DISPLAY_COUNT)(
   1001         hwc2_device_t* device);
   1002 
   1003 /* registerCallback(..., descriptor, callbackData, pointer)
   1004  * Descriptor: HWC2_FUNCTION_REGISTER_CALLBACK
   1005  * Must be provided by all HWC2 devices
   1006  *
   1007  * Provides a callback for the device to call. All callbacks take a callbackData
   1008  * item as the first parameter, so this value should be stored with the callback
   1009  * for later use. The callbackData may differ from one callback to another. If
   1010  * this function is called multiple times with the same descriptor, later
   1011  * callbacks replace earlier ones.
   1012  *
   1013  * Parameters:
   1014  *   descriptor - which callback should be set
   1015  *   callBackdata - opaque data which must be passed back through the callback
   1016  *   pointer - a non-NULL function pointer corresponding to the descriptor
   1017  *
   1018  * Returns HWC2_ERROR_NONE or one of the following errors:
   1019  *   HWC2_ERROR_BAD_PARAMETER - descriptor was invalid
   1020  */
   1021 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_REGISTER_CALLBACK)(
   1022         hwc2_device_t* device,
   1023         int32_t /*hwc2_callback_descriptor_t*/ descriptor,
   1024         hwc2_callback_data_t callbackData, hwc2_function_pointer_t pointer);
   1025 
   1026 /* getDataspaceSaturationMatrix(..., dataspace, outMatrix)
   1027  * Descriptor: HWC2_FUNCTION_GET_DATASPACE_SATURATION_MATRIX
   1028  * Provided by HWC2 devices which don't return nullptr function pointer.
   1029  *
   1030  * Get the saturation matrix of the specified dataspace. The saturation matrix
   1031  * can be used to approximate the dataspace saturation operation performed by
   1032  * the HWC2 device when non-colorimetric mapping is allowed. It is to be
   1033  * applied on linear pixel values.
   1034  *
   1035  * Parameters:
   1036  *   dataspace - the dataspace to query for
   1037  *   outMatrix - a column-major 4x4 matrix (16 floats). It must be an identity
   1038  *       matrix unless dataspace is HAL_DATASPACE_SRGB_LINEAR.
   1039  *
   1040  * Returns HWC2_ERROR_NONE or one of the following errors:
   1041  *   HWC2_ERROR_BAD_PARAMETER - dataspace was invalid
   1042  */
   1043 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_DATASPACE_SATURATION_MATRIX)(
   1044         hwc2_device_t* device, int32_t /*android_dataspace_t*/ dataspace,
   1045         float* outMatrix);
   1046 
   1047 /*
   1048  * Display Functions
   1049  *
   1050  * All of these functions take as their first two parameters a device pointer
   1051  * and a display handle, so these parameters are omitted from the described
   1052  * parameter lists.
   1053  */
   1054 
   1055 /* acceptDisplayChanges(...)
   1056  * Descriptor: HWC2_FUNCTION_ACCEPT_DISPLAY_CHANGES
   1057  * Must be provided by all HWC2 devices
   1058  *
   1059  * Accepts the changes required by the device from the previous validateDisplay
   1060  * call (which may be queried using getChangedCompositionTypes) and revalidates
   1061  * the display. This function is equivalent to requesting the changed types from
   1062  * getChangedCompositionTypes, setting those types on the corresponding layers,
   1063  * and then calling validateDisplay again.
   1064  *
   1065  * After this call it must be valid to present this display. Calling this after
   1066  * validateDisplay returns 0 changes must succeed with HWC2_ERROR_NONE, but
   1067  * should have no other effect.
   1068  *
   1069  * Returns HWC2_ERROR_NONE or one of the following errors:
   1070  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1071  *   HWC2_ERROR_NOT_VALIDATED - validateDisplay has not been called
   1072  */
   1073 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_ACCEPT_DISPLAY_CHANGES)(
   1074         hwc2_device_t* device, hwc2_display_t display);
   1075 
   1076 /* createLayer(..., outLayer)
   1077  * Descriptor: HWC2_FUNCTION_CREATE_LAYER
   1078  * Must be provided by all HWC2 devices
   1079  *
   1080  * Creates a new layer on the given display.
   1081  *
   1082  * Parameters:
   1083  *   outLayer - the handle of the new layer; pointer will be non-NULL
   1084  *
   1085  * Returns HWC2_ERROR_NONE or one of the following errors:
   1086  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1087  *   HWC2_ERROR_NO_RESOURCES - the device was unable to create this layer
   1088  */
   1089 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_CREATE_LAYER)(hwc2_device_t* device,
   1090         hwc2_display_t display, hwc2_layer_t* outLayer);
   1091 
   1092 /* destroyLayer(..., layer)
   1093  * Descriptor: HWC2_FUNCTION_DESTROY_LAYER
   1094  * Must be provided by all HWC2 devices
   1095  *
   1096  * Destroys the given layer.
   1097  *
   1098  * Parameters:
   1099  *   layer - the handle of the layer to destroy
   1100  *
   1101  * Returns HWC2_ERROR_NONE or one of the following errors:
   1102  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1103  *   HWC2_ERROR_BAD_LAYER - an invalid layer handle was passed in
   1104  */
   1105 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_DESTROY_LAYER)(
   1106         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer);
   1107 
   1108 /* getActiveConfig(..., outConfig)
   1109  * Descriptor: HWC2_FUNCTION_GET_ACTIVE_CONFIG
   1110  * Must be provided by all HWC2 devices
   1111  *
   1112  * Retrieves which display configuration is currently active.
   1113  *
   1114  * If no display configuration is currently active, this function must return
   1115  * HWC2_ERROR_BAD_CONFIG and place no configuration handle in outConfig. It is
   1116  * the responsibility of the client to call setActiveConfig with a valid
   1117  * configuration before attempting to present anything on the display.
   1118  *
   1119  * Parameters:
   1120  *   outConfig - the currently active display configuration; pointer will be
   1121  *       non-NULL
   1122  *
   1123  * Returns HWC2_ERROR_NONE or one of the following errors:
   1124  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1125  *   HWC2_ERROR_BAD_CONFIG - no configuration is currently active
   1126  */
   1127 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_ACTIVE_CONFIG)(
   1128         hwc2_device_t* device, hwc2_display_t display,
   1129         hwc2_config_t* outConfig);
   1130 
   1131 /* getChangedCompositionTypes(..., outNumElements, outLayers, outTypes)
   1132  * Descriptor: HWC2_FUNCTION_GET_CHANGED_COMPOSITION_TYPES
   1133  * Must be provided by all HWC2 devices
   1134  *
   1135  * Retrieves the layers for which the device requires a different composition
   1136  * type than had been set prior to the last call to validateDisplay. The client
   1137  * will either update its state with these types and call acceptDisplayChanges,
   1138  * or will set new types and attempt to validate the display again.
   1139  *
   1140  * outLayers and outTypes may be NULL to retrieve the number of elements which
   1141  * will be returned. The number of elements returned must be the same as the
   1142  * value returned in outNumTypes from the last call to validateDisplay.
   1143  *
   1144  * Parameters:
   1145  *   outNumElements - if outLayers or outTypes were NULL, the number of layers
   1146  *       and types which would have been returned; if both were non-NULL, the
   1147  *       number of elements returned in outLayers and outTypes, which must not
   1148  *       exceed the value stored in outNumElements prior to the call; pointer
   1149  *       will be non-NULL
   1150  *   outLayers - an array of layer handles
   1151  *   outTypes - an array of composition types, each corresponding to an element
   1152  *       of outLayers
   1153  *
   1154  * Returns HWC2_ERROR_NONE or one of the following errors:
   1155  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1156  *   HWC2_ERROR_NOT_VALIDATED - validateDisplay has not been called for this
   1157  *       display
   1158  */
   1159 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_CHANGED_COMPOSITION_TYPES)(
   1160         hwc2_device_t* device, hwc2_display_t display,
   1161         uint32_t* outNumElements, hwc2_layer_t* outLayers,
   1162         int32_t* /*hwc2_composition_t*/ outTypes);
   1163 
   1164 /* getClientTargetSupport(..., width, height, format, dataspace)
   1165  * Descriptor: HWC2_FUNCTION_GET_CLIENT_TARGET_SUPPORT
   1166  * Must be provided by all HWC2 devices
   1167  *
   1168  * Returns whether a client target with the given properties can be handled by
   1169  * the device.
   1170  *
   1171  * The valid formats can be found in android_pixel_format_t in
   1172  * <system/graphics.h>.
   1173  *
   1174  * For more about dataspaces, see setLayerDataspace.
   1175  *
   1176  * This function must return true for a client target with width and height
   1177  * equal to the active display configuration dimensions,
   1178  * HAL_PIXEL_FORMAT_RGBA_8888, and HAL_DATASPACE_UNKNOWN. It is not required to
   1179  * return true for any other configuration.
   1180  *
   1181  * Parameters:
   1182  *   width - client target width in pixels
   1183  *   height - client target height in pixels
   1184  *   format - client target format
   1185  *   dataspace - client target dataspace, as described in setLayerDataspace
   1186  *
   1187  * Returns HWC2_ERROR_NONE if the given configuration is supported or one of the
   1188  * following errors:
   1189  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1190  *   HWC2_ERROR_UNSUPPORTED - the given configuration is not supported
   1191  */
   1192 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_CLIENT_TARGET_SUPPORT)(
   1193         hwc2_device_t* device, hwc2_display_t display, uint32_t width,
   1194         uint32_t height, int32_t /*android_pixel_format_t*/ format,
   1195         int32_t /*android_dataspace_t*/ dataspace);
   1196 
   1197 /* getColorModes(..., outNumModes, outModes)
   1198  * Descriptor: HWC2_FUNCTION_GET_COLOR_MODES
   1199  * Must be provided by all HWC2 devices
   1200  *
   1201  * Returns the color modes supported on this display.
   1202  *
   1203  * The valid color modes can be found in android_color_mode_t in
   1204  * <system/graphics.h>. All HWC2 devices must support at least
   1205  * HAL_COLOR_MODE_NATIVE.
   1206  *
   1207  * outNumModes may be NULL to retrieve the number of modes which will be
   1208  * returned.
   1209  *
   1210  * Parameters:
   1211  *   outNumModes - if outModes was NULL, the number of modes which would have
   1212  *       been returned; if outModes was not NULL, the number of modes returned,
   1213  *       which must not exceed the value stored in outNumModes prior to the
   1214  *       call; pointer will be non-NULL
   1215  *   outModes - an array of color modes
   1216  *
   1217  * Returns HWC2_ERROR_NONE or one of the following errors:
   1218  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1219  */
   1220 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_COLOR_MODES)(
   1221         hwc2_device_t* device, hwc2_display_t display, uint32_t* outNumModes,
   1222         int32_t* /*android_color_mode_t*/ outModes);
   1223 
   1224 /* getRenderIntents(..., mode, outNumIntents, outIntents)
   1225  * Descriptor: HWC2_FUNCTION_GET_RENDER_INTENTS
   1226  * Provided by HWC2 devices which don't return nullptr function pointer.
   1227  *
   1228  * Returns the render intents supported on this display.
   1229  *
   1230  * The valid render intents can be found in android_render_intent_v1_1_t in
   1231  * <system/graphics.h>. All HWC2 devices must support at least
   1232  * HAL_RENDER_INTENT_COLORIMETRIC.
   1233  *
   1234  * outNumIntents may be NULL to retrieve the number of intents which will be
   1235  * returned.
   1236  *
   1237  * Parameters:
   1238  *   mode - the color mode to query the render intents for
   1239  *   outNumIntents - if outIntents was NULL, the number of intents which would
   1240  *       have been returned; if outIntents was not NULL, the number of intents
   1241  *       returned, which must not exceed the value stored in outNumIntents
   1242  *       prior to the call; pointer will be non-NULL
   1243  *   outIntents - an array of render intents
   1244  *
   1245  * Returns HWC2_ERROR_NONE or one of the following errors:
   1246  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1247  */
   1248 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_RENDER_INTENTS)(
   1249         hwc2_device_t* device, hwc2_display_t display, int32_t mode,
   1250         uint32_t* outNumIntents,
   1251         int32_t* /*android_render_intent_v1_1_t*/ outIntents);
   1252 
   1253 /* getDisplayAttribute(..., config, attribute, outValue)
   1254  * Descriptor: HWC2_FUNCTION_GET_DISPLAY_ATTRIBUTE
   1255  * Must be provided by all HWC2 devices
   1256  *
   1257  * Returns a display attribute value for a particular display configuration.
   1258  *
   1259  * Any attribute which is not supported or for which the value is unknown by the
   1260  * device must return a value of -1.
   1261  *
   1262  * Parameters:
   1263  *   config - the display configuration for which to return attribute values
   1264  *   attribute - the attribute to query
   1265  *   outValue - the value of the attribute; the pointer will be non-NULL
   1266  *
   1267  * Returns HWC2_ERROR_NONE or one of the following errors:
   1268  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1269  *   HWC2_ERROR_BAD_CONFIG - config does not name a valid configuration for this
   1270  *       display
   1271  */
   1272 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_DISPLAY_ATTRIBUTE)(
   1273         hwc2_device_t* device, hwc2_display_t display, hwc2_config_t config,
   1274         int32_t /*hwc2_attribute_t*/ attribute, int32_t* outValue);
   1275 
   1276 /* getDisplayConfigs(..., outNumConfigs, outConfigs)
   1277  * Descriptor: HWC2_FUNCTION_GET_DISPLAY_CONFIGS
   1278  * Must be provided by all HWC2 devices
   1279  *
   1280  * Returns handles for all of the valid display configurations on this display.
   1281  *
   1282  * outConfigs may be NULL to retrieve the number of elements which will be
   1283  * returned.
   1284  *
   1285  * Parameters:
   1286  *   outNumConfigs - if outConfigs was NULL, the number of configurations which
   1287  *       would have been returned; if outConfigs was not NULL, the number of
   1288  *       configurations returned, which must not exceed the value stored in
   1289  *       outNumConfigs prior to the call; pointer will be non-NULL
   1290  *   outConfigs - an array of configuration handles
   1291  *
   1292  * Returns HWC2_ERROR_NONE or one of the following errors:
   1293  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1294  */
   1295 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_DISPLAY_CONFIGS)(
   1296         hwc2_device_t* device, hwc2_display_t display, uint32_t* outNumConfigs,
   1297         hwc2_config_t* outConfigs);
   1298 
   1299 /* getDisplayName(..., outSize, outName)
   1300  * Descriptor: HWC2_FUNCTION_GET_DISPLAY_NAME
   1301  * Must be provided by all HWC2 devices
   1302  *
   1303  * Returns a human-readable version of the display's name.
   1304  *
   1305  * outName may be NULL to retrieve the length of the name.
   1306  *
   1307  * Parameters:
   1308  *   outSize - if outName was NULL, the number of bytes needed to return the
   1309  *       name if outName was not NULL, the number of bytes written into it,
   1310  *       which must not exceed the value stored in outSize prior to the call;
   1311  *       pointer will be non-NULL
   1312  *   outName - the display's name
   1313  *
   1314  * Returns HWC2_ERROR_NONE or one of the following errors:
   1315  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1316  */
   1317 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_DISPLAY_NAME)(
   1318         hwc2_device_t* device, hwc2_display_t display, uint32_t* outSize,
   1319         char* outName);
   1320 
   1321 /* getDisplayRequests(..., outDisplayRequests, outNumElements, outLayers,
   1322  *     outLayerRequests)
   1323  * Descriptor: HWC2_FUNCTION_GET_DISPLAY_REQUESTS
   1324  * Must be provided by all HWC2 devices
   1325  *
   1326  * Returns the display requests and the layer requests required for the last
   1327  * validated configuration.
   1328  *
   1329  * Display requests provide information about how the client should handle the
   1330  * client target. Layer requests provide information about how the client
   1331  * should handle an individual layer.
   1332  *
   1333  * If outLayers or outLayerRequests is NULL, the required number of layers and
   1334  * requests must be returned in outNumElements, but this number may also be
   1335  * obtained from validateDisplay as outNumRequests (outNumElements must be equal
   1336  * to the value returned in outNumRequests from the last call to
   1337  * validateDisplay).
   1338  *
   1339  * Parameters:
   1340  *   outDisplayRequests - the display requests for the current validated state
   1341  *   outNumElements - if outLayers or outLayerRequests were NULL, the number of
   1342  *       elements which would have been returned, which must be equal to the
   1343  *       value returned in outNumRequests from the last validateDisplay call on
   1344  *       this display; if both were not NULL, the number of elements in
   1345  *       outLayers and outLayerRequests, which must not exceed the value stored
   1346  *       in outNumElements prior to the call; pointer will be non-NULL
   1347  *   outLayers - an array of layers which all have at least one request
   1348  *   outLayerRequests - the requests corresponding to each element of outLayers
   1349  *
   1350  * Returns HWC2_ERROR_NONE or one of the following errors:
   1351  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1352  *   HWC2_ERROR_NOT_VALIDATED - validateDisplay has not been called for this
   1353  *       display
   1354  */
   1355 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_DISPLAY_REQUESTS)(
   1356         hwc2_device_t* device, hwc2_display_t display,
   1357         int32_t* /*hwc2_display_request_t*/ outDisplayRequests,
   1358         uint32_t* outNumElements, hwc2_layer_t* outLayers,
   1359         int32_t* /*hwc2_layer_request_t*/ outLayerRequests);
   1360 
   1361 /* getDisplayType(..., outType)
   1362  * Descriptor: HWC2_FUNCTION_GET_DISPLAY_TYPE
   1363  * Must be provided by all HWC2 devices
   1364  *
   1365  * Returns whether the given display is a physical or virtual display.
   1366  *
   1367  * Parameters:
   1368  *   outType - the type of the display; pointer will be non-NULL
   1369  *
   1370  * Returns HWC2_ERROR_NONE or one of the following errors:
   1371  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1372  */
   1373 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_DISPLAY_TYPE)(
   1374         hwc2_device_t* device, hwc2_display_t display,
   1375         int32_t* /*hwc2_display_type_t*/ outType);
   1376 
   1377 /* getDozeSupport(..., outSupport)
   1378  * Descriptor: HWC2_FUNCTION_GET_DOZE_SUPPORT
   1379  * Must be provided by all HWC2 devices
   1380  *
   1381  * Returns whether the given display supports HWC2_POWER_MODE_DOZE and
   1382  * HWC2_POWER_MODE_DOZE_SUSPEND. DOZE_SUSPEND may not provide any benefit over
   1383  * DOZE (see the definition of hwc2_power_mode_t for more information), but if
   1384  * both DOZE and DOZE_SUSPEND are no different from HWC2_POWER_MODE_ON, the
   1385  * device should not claim support.
   1386  *
   1387  * Parameters:
   1388  *   outSupport - whether the display supports doze modes (1 for yes, 0 for no);
   1389  *       pointer will be non-NULL
   1390  *
   1391  * Returns HWC2_ERROR_NONE or one of the following errors:
   1392  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1393  */
   1394 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_DOZE_SUPPORT)(
   1395         hwc2_device_t* device, hwc2_display_t display, int32_t* outSupport);
   1396 
   1397 /* getHdrCapabilities(..., outNumTypes, outTypes, outMaxLuminance,
   1398  *     outMaxAverageLuminance, outMinLuminance)
   1399  * Descriptor: HWC2_FUNCTION_GET_HDR_CAPABILITIES
   1400  * Must be provided by all HWC2 devices
   1401  *
   1402  * Returns the high dynamic range (HDR) capabilities of the given display, which
   1403  * are invariant with regard to the active configuration.
   1404  *
   1405  * Displays which are not HDR-capable must return no types in outTypes and set
   1406  * outNumTypes to 0.
   1407  *
   1408  * If outTypes is NULL, the required number of HDR types must be returned in
   1409  * outNumTypes.
   1410  *
   1411  * Parameters:
   1412  *   outNumTypes - if outTypes was NULL, the number of types which would have
   1413  *       been returned; if it was not NULL, the number of types stored in
   1414  *       outTypes, which must not exceed the value stored in outNumTypes prior
   1415  *       to the call; pointer will be non-NULL
   1416  *   outTypes - an array of HDR types, may have 0 elements if the display is not
   1417  *       HDR-capable
   1418  *   outMaxLuminance - the desired content maximum luminance for this display in
   1419  *       cd/m^2; pointer will be non-NULL
   1420  *   outMaxAverageLuminance - the desired content maximum frame-average
   1421  *       luminance for this display in cd/m^2; pointer will be non-NULL
   1422  *   outMinLuminance - the desired content minimum luminance for this display in
   1423  *       cd/m^2; pointer will be non-NULL
   1424  *
   1425  * Returns HWC2_ERROR_NONE or one of the following errors:
   1426  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1427  */
   1428 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_HDR_CAPABILITIES)(
   1429         hwc2_device_t* device, hwc2_display_t display, uint32_t* outNumTypes,
   1430         int32_t* /*android_hdr_t*/ outTypes, float* outMaxLuminance,
   1431         float* outMaxAverageLuminance, float* outMinLuminance);
   1432 
   1433 /* getReleaseFences(..., outNumElements, outLayers, outFences)
   1434  * Descriptor: HWC2_FUNCTION_GET_RELEASE_FENCES
   1435  * Must be provided by all HWC2 devices
   1436  *
   1437  * Retrieves the release fences for device layers on this display which will
   1438  * receive new buffer contents this frame.
   1439  *
   1440  * A release fence is a file descriptor referring to a sync fence object which
   1441  * will be signaled after the device has finished reading from the buffer
   1442  * presented in the prior frame. This indicates that it is safe to start writing
   1443  * to the buffer again. If a given layer's fence is not returned from this
   1444  * function, it will be assumed that the buffer presented on the previous frame
   1445  * is ready to be written.
   1446  *
   1447  * The fences returned by this function should be unique for each layer (even if
   1448  * they point to the same underlying sync object), and ownership of the fences
   1449  * is transferred to the client, which is responsible for closing them.
   1450  *
   1451  * If outLayers or outFences is NULL, the required number of layers and fences
   1452  * must be returned in outNumElements.
   1453  *
   1454  * Parameters:
   1455  *   outNumElements - if outLayers or outFences were NULL, the number of
   1456  *       elements which would have been returned; if both were not NULL, the
   1457  *       number of elements in outLayers and outFences, which must not exceed
   1458  *       the value stored in outNumElements prior to the call; pointer will be
   1459  *       non-NULL
   1460  *   outLayers - an array of layer handles
   1461  *   outFences - an array of sync fence file descriptors as described above,
   1462  *       each corresponding to an element of outLayers
   1463  *
   1464  * Returns HWC2_ERROR_NONE or one of the following errors:
   1465  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1466  */
   1467 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_RELEASE_FENCES)(
   1468         hwc2_device_t* device, hwc2_display_t display, uint32_t* outNumElements,
   1469         hwc2_layer_t* outLayers, int32_t* outFences);
   1470 
   1471 /* presentDisplay(..., outPresentFence)
   1472  * Descriptor: HWC2_FUNCTION_PRESENT_DISPLAY
   1473  * Must be provided by all HWC2 devices
   1474  *
   1475  * Presents the current display contents on the screen (or in the case of
   1476  * virtual displays, into the output buffer).
   1477  *
   1478  * Prior to calling this function, the display must be successfully validated
   1479  * with validateDisplay. Note that setLayerBuffer and setLayerSurfaceDamage
   1480  * specifically do not count as layer state, so if there are no other changes
   1481  * to the layer state (or to the buffer's properties as described in
   1482  * setLayerBuffer), then it is safe to call this function without first
   1483  * validating the display.
   1484  *
   1485  * If this call succeeds, outPresentFence will be populated with a file
   1486  * descriptor referring to a present sync fence object. For physical displays,
   1487  * this fence will be signaled at the vsync when the result of composition of
   1488  * this frame starts to appear (for video-mode panels) or starts to transfer to
   1489  * panel memory (for command-mode panels). For virtual displays, this fence will
   1490  * be signaled when writes to the output buffer have completed and it is safe to
   1491  * read from it.
   1492  *
   1493  * Parameters:
   1494  *   outPresentFence - a sync fence file descriptor as described above; pointer
   1495  *       will be non-NULL
   1496  *
   1497  * Returns HWC2_ERROR_NONE or one of the following errors:
   1498  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1499  *   HWC2_ERROR_NO_RESOURCES - no valid output buffer has been set for a virtual
   1500  *       display
   1501  *   HWC2_ERROR_NOT_VALIDATED - validateDisplay has not successfully been called
   1502  *       for this display
   1503  */
   1504 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_PRESENT_DISPLAY)(
   1505         hwc2_device_t* device, hwc2_display_t display,
   1506         int32_t* outPresentFence);
   1507 
   1508 /* setActiveConfig(..., config)
   1509  * Descriptor: HWC2_FUNCTION_SET_ACTIVE_CONFIG
   1510  * Must be provided by all HWC2 devices
   1511  *
   1512  * Sets the active configuration for this display. Upon returning, the given
   1513  * display configuration should be active and remain so until either this
   1514  * function is called again or the display is disconnected.
   1515  *
   1516  * Parameters:
   1517  *   config - the new display configuration
   1518  *
   1519  * Returns HWC2_ERROR_NONE or one of the following errors:
   1520  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1521  *   HWC2_ERROR_BAD_CONFIG - the configuration handle passed in is not valid for
   1522  *       this display
   1523  */
   1524 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_ACTIVE_CONFIG)(
   1525         hwc2_device_t* device, hwc2_display_t display, hwc2_config_t config);
   1526 
   1527 /* setClientTarget(..., target, acquireFence, dataspace, damage)
   1528  * Descriptor: HWC2_FUNCTION_SET_CLIENT_TARGET
   1529  * Must be provided by all HWC2 devices
   1530  *
   1531  * Sets the buffer handle which will receive the output of client composition.
   1532  * Layers marked as HWC2_COMPOSITION_CLIENT will be composited into this buffer
   1533  * prior to the call to presentDisplay, and layers not marked as
   1534  * HWC2_COMPOSITION_CLIENT should be composited with this buffer by the device.
   1535  *
   1536  * The buffer handle provided may be null if no layers are being composited by
   1537  * the client. This must not result in an error (unless an invalid display
   1538  * handle is also provided).
   1539  *
   1540  * Also provides a file descriptor referring to an acquire sync fence object,
   1541  * which will be signaled when it is safe to read from the client target buffer.
   1542  * If it is already safe to read from this buffer, -1 may be passed instead.
   1543  * The device must ensure that it is safe for the client to close this file
   1544  * descriptor at any point after this function is called.
   1545  *
   1546  * For more about dataspaces, see setLayerDataspace.
   1547  *
   1548  * The damage parameter describes a surface damage region as defined in the
   1549  * description of setLayerSurfaceDamage.
   1550  *
   1551  * Will be called before presentDisplay if any of the layers are marked as
   1552  * HWC2_COMPOSITION_CLIENT. If no layers are so marked, then it is not
   1553  * necessary to call this function. It is not necessary to call validateDisplay
   1554  * after changing the target through this function.
   1555  *
   1556  * Parameters:
   1557  *   target - the new target buffer
   1558  *   acquireFence - a sync fence file descriptor as described above
   1559  *   dataspace - the dataspace of the buffer, as described in setLayerDataspace
   1560  *   damage - the surface damage region
   1561  *
   1562  * Returns HWC2_ERROR_NONE or one of the following errors:
   1563  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1564  *   HWC2_ERROR_BAD_PARAMETER - the new target handle was invalid
   1565  */
   1566 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_CLIENT_TARGET)(
   1567         hwc2_device_t* device, hwc2_display_t display, buffer_handle_t target,
   1568         int32_t acquireFence, int32_t /*android_dataspace_t*/ dataspace,
   1569         hwc_region_t damage);
   1570 
   1571 /* setColorMode(..., mode)
   1572  * Descriptor: HWC2_FUNCTION_SET_COLOR_MODE
   1573  * Must be provided by all HWC2 devices
   1574  *
   1575  * Sets the color mode of the given display.
   1576  *
   1577  * This must be called outside of validateDisplay/presentDisplay, and it takes
   1578  * effect on next presentDisplay.
   1579  *
   1580  * The valid color modes can be found in android_color_mode_t in
   1581  * <system/graphics.h>. All HWC2 devices must support at least
   1582  * HAL_COLOR_MODE_NATIVE, and displays are assumed to be in this mode upon
   1583  * hotplug.
   1584  *
   1585  * Parameters:
   1586  *   mode - the mode to set
   1587  *
   1588  * Returns HWC2_ERROR_NONE or one of the following errors:
   1589  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1590  *   HWC2_ERROR_BAD_PARAMETER - mode is not a valid color mode
   1591  *   HWC2_ERROR_UNSUPPORTED - mode is not supported on this display
   1592  */
   1593 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_COLOR_MODE)(
   1594         hwc2_device_t* device, hwc2_display_t display,
   1595         int32_t /*android_color_mode_t*/ mode);
   1596 
   1597 /* setColorModeWithIntent(..., mode, intent)
   1598  * Descriptor: HWC2_FUNCTION_SET_COLOR_MODE_WITH_RENDER_INTENT
   1599  * Provided by HWC2 devices which don't return nullptr function pointer.
   1600  *
   1601  * This must be called outside of validateDisplay/presentDisplay, and it takes
   1602  * effect on next presentDisplay.
   1603  *
   1604  * The valid color modes and render intents can be found in
   1605  * android_color_mode_t and android_render_intent_v1_1_t in
   1606  * <system/graphics.h>. All HWC2 devices must support at least
   1607  * HAL_COLOR_MODE_NATIVE and HAL_RENDER_INTENT_COLORIMETRIC, and displays are
   1608  * assumed to be in this mode and intent upon hotplug.
   1609  *
   1610  * Parameters:
   1611  *   mode - the mode to set
   1612  *   intent - the intent to set
   1613  *
   1614  * Returns HWC2_ERROR_NONE or one of the following errors:
   1615  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1616  *   HWC2_ERROR_BAD_PARAMETER - mode/intent is not a valid color mode or
   1617  *       render intent
   1618  *   HWC2_ERROR_UNSUPPORTED - mode or intent is not supported on this display
   1619  */
   1620 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_COLOR_MODE_WITH_RENDER_INTENT)(
   1621         hwc2_device_t* device, hwc2_display_t display,
   1622         int32_t /*android_color_mode_t*/ mode,
   1623         int32_t /*android_render_intent_v1_1_t */ intent);
   1624 
   1625 /* setColorTransform(..., matrix, hint)
   1626  * Descriptor: HWC2_FUNCTION_SET_COLOR_TRANSFORM
   1627  * Must be provided by all HWC2 devices
   1628  *
   1629  * Sets a color transform which will be applied after composition.
   1630  *
   1631  * If hint is not HAL_COLOR_TRANSFORM_ARBITRARY, then the device may use the
   1632  * hint to apply the desired color transform instead of using the color matrix
   1633  * directly.
   1634  *
   1635  * If the device is not capable of either using the hint or the matrix to apply
   1636  * the desired color transform, it should force all layers to client composition
   1637  * during validateDisplay.
   1638  *
   1639  * If HWC2_CAPABILITY_SKIP_CLIENT_COLOR_TRANSFORM is present, then the client
   1640  * will never apply the color transform during client composition, even if all
   1641  * layers are being composed by the client.
   1642  *
   1643  * The matrix provided is an affine color transformation of the following form:
   1644  *
   1645  * |r.r r.g r.b 0|
   1646  * |g.r g.g g.b 0|
   1647  * |b.r b.g b.b 0|
   1648  * |Tr  Tg  Tb  1|
   1649  *
   1650  * This matrix will be provided in row-major form: {r.r, r.g, r.b, 0, g.r, ...}.
   1651  *
   1652  * Given a matrix of this form and an input color [R_in, G_in, B_in], the output
   1653  * color [R_out, G_out, B_out] will be:
   1654  *
   1655  * R_out = R_in * r.r + G_in * g.r + B_in * b.r + Tr
   1656  * G_out = R_in * r.g + G_in * g.g + B_in * b.g + Tg
   1657  * B_out = R_in * r.b + G_in * g.b + B_in * b.b + Tb
   1658  *
   1659  * Parameters:
   1660  *   matrix - a 4x4 transform matrix (16 floats) as described above
   1661  *   hint - a hint value which may be used instead of the given matrix unless it
   1662  *       is HAL_COLOR_TRANSFORM_ARBITRARY
   1663  *
   1664  * Returns HWC2_ERROR_NONE or one of the following errors:
   1665  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1666  *   HWC2_ERROR_BAD_PARAMETER - hint is not a valid color transform hint
   1667  */
   1668 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_COLOR_TRANSFORM)(
   1669         hwc2_device_t* device, hwc2_display_t display, const float* matrix,
   1670         int32_t /*android_color_transform_t*/ hint);
   1671 
   1672 /* getPerFrameMetadataKeys(..., outKeys)
   1673  * Descriptor: HWC2_FUNCTION_GET_PER_FRAME_METADATA_KEYS
   1674  * Optional for HWC2 devices
   1675  *
   1676  * If supported (getFunction(HWC2_FUNCTION_GET_PER_FRAME_METADATA_KEYS) is non-null),
   1677  * getPerFrameMetadataKeys returns the list of supported PerFrameMetadataKeys
   1678  * which are invariant with regard to the active configuration.
   1679  *
   1680  * Devices which are not HDR-capable, must return null when getFunction is called
   1681  * with HWC2_FUNCTION_GET_PER_FRAME_METADATA_KEYS.
   1682  *
   1683  * If outKeys is NULL, the required number of PerFrameMetadataKey keys
   1684  * must be returned in outNumKeys.
   1685  *
   1686  * Parameters:
   1687  *   outNumKeys - if outKeys is NULL, the number of keys which would have
   1688  *       been returned; if outKeys is not NULL, the number of keys stored in
   1689  *       outKeys, which must not exceed the value stored in outNumKeys prior
   1690  *       to the call; pointer will be non-NULL
   1691  *   outKeys - an array of hwc2_per_frame_metadata_key_t keys
   1692  *
   1693  * Returns HWC2_ERROR_NONE or one of the following errors:
   1694  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1695  */
   1696 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_PER_FRAME_METADATA_KEYS)(
   1697         hwc2_device_t* device, hwc2_display_t display, uint32_t* outNumKeys,
   1698         int32_t* /*hwc2_per_frame_metadata_key_t*/ outKeys);
   1699 
   1700 /* setOutputBuffer(..., buffer, releaseFence)
   1701  * Descriptor: HWC2_FUNCTION_SET_OUTPUT_BUFFER
   1702  * Must be provided by all HWC2 devices
   1703  *
   1704  * Sets the output buffer for a virtual display. That is, the buffer to which
   1705  * the composition result will be written.
   1706  *
   1707  * Also provides a file descriptor referring to a release sync fence object,
   1708  * which will be signaled when it is safe to write to the output buffer. If it
   1709  * is already safe to write to the output buffer, -1 may be passed instead. The
   1710  * device must ensure that it is safe for the client to close this file
   1711  * descriptor at any point after this function is called.
   1712  *
   1713  * Must be called at least once before presentDisplay, but does not have any
   1714  * interaction with layer state or display validation.
   1715  *
   1716  * Parameters:
   1717  *   buffer - the new output buffer
   1718  *   releaseFence - a sync fence file descriptor as described above
   1719  *
   1720  * Returns HWC2_ERROR_NONE or one of the following errors:
   1721  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1722  *   HWC2_ERROR_BAD_PARAMETER - the new output buffer handle was invalid
   1723  *   HWC2_ERROR_UNSUPPORTED - display does not refer to a virtual display
   1724  */
   1725 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_OUTPUT_BUFFER)(
   1726         hwc2_device_t* device, hwc2_display_t display, buffer_handle_t buffer,
   1727         int32_t releaseFence);
   1728 
   1729 /* setPowerMode(..., mode)
   1730  * Descriptor: HWC2_FUNCTION_SET_POWER_MODE
   1731  * Must be provided by all HWC2 devices
   1732  *
   1733  * Sets the power mode of the given display. The transition must be complete
   1734  * when this function returns. It is valid to call this function multiple times
   1735  * with the same power mode.
   1736  *
   1737  * All displays must support HWC2_POWER_MODE_ON and HWC2_POWER_MODE_OFF. Whether
   1738  * a display supports HWC2_POWER_MODE_DOZE or HWC2_POWER_MODE_DOZE_SUSPEND may
   1739  * be queried using getDozeSupport.
   1740  *
   1741  * Parameters:
   1742  *   mode - the new power mode
   1743  *
   1744  * Returns HWC2_ERROR_NONE or one of the following errors:
   1745  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1746  *   HWC2_ERROR_BAD_PARAMETER - mode was not a valid power mode
   1747  *   HWC2_ERROR_UNSUPPORTED - mode was a valid power mode, but is not supported
   1748  *       on this display
   1749  */
   1750 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_POWER_MODE)(
   1751         hwc2_device_t* device, hwc2_display_t display,
   1752         int32_t /*hwc2_power_mode_t*/ mode);
   1753 
   1754 /* getReadbackBufferAttributes(..., outFormat, outDataspace)
   1755  * Optional for HWC2 devices
   1756  *
   1757  * Returns the format which should be used when allocating a buffer for use by
   1758  * device readback as well as the dataspace in which its contents should be
   1759  * interpreted.
   1760  *
   1761  * If readback is not supported by this HWC implementation, this call will also
   1762  * be able to return HWC2_ERROR_UNSUPPORTED so we can fall back to another method.
   1763  * Returning NULL to a getFunction request for this function will also indicate
   1764  * that readback is not supported.
   1765  *
   1766  * The width and height of this buffer will be those of the currently-active
   1767  * display configuration, and the usage flags will consist of the following:
   1768  *   BufferUsage::CPU_READ | BufferUsage::GPU_TEXTURE |
   1769  *   BufferUsage::COMPOSER_OUTPUT
   1770  *
   1771  * The format and dataspace provided must be sufficient such that if a
   1772  * correctly-configured buffer is passed into setReadbackBuffer, filled by
   1773  * the device, and then displayed by the client as a full-screen buffer, the
   1774  * output of the display remains the same (subject to the note about protected
   1775  * content in the description of setReadbackBuffer).
   1776  *
   1777  * If the active configuration or color mode of this display has changed since
   1778  * the previous call to this function, it will be called again prior to setting
   1779  * a readback buffer such that the returned format and dataspace can be updated
   1780  * accordingly.
   1781  *
   1782  * Parameters:
   1783  *   outFormat - the format the client should use when allocating a device
   1784  *       readback buffer; pointer will be non-NULL
   1785  *   outDataspace - the dataspace the client will use when interpreting the
   1786  *       contents of a device readback buffer; pointer will be non-NULL
   1787  *
   1788  * Returns HWC2_ERROR_NONE or one of the following errors:
   1789  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1790  *
   1791  * See also:
   1792  *   setReadbackBuffer
   1793  *   getReadbackBufferFence
   1794  */
   1795 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_READBACK_BUFFER_ATTRIBUTES)(
   1796         hwc2_device_t* device, hwc2_display_t display,
   1797         int32_t* /*android_pixel_format_t*/ outFormat,
   1798         int32_t* /*android_dataspace_t*/ outDataspace);
   1799 
   1800 /* getReadbackBufferFence(..., outFence)
   1801  * Optional for HWC2 devices
   1802  *
   1803  * Returns an acquire sync fence file descriptor which will signal when the
   1804  * buffer provided to setReadbackBuffer has been filled by the device and is
   1805  * safe for the client to read.
   1806  *
   1807  * If it is already safe to read from this buffer, -1 may be returned instead.
   1808  * The client takes ownership of this file descriptor and is responsible for
   1809  * closing it when it is no longer needed.
   1810  *
   1811  * This function will be called immediately after the composition cycle being
   1812  * captured into the readback buffer. The complete ordering of a readback buffer
   1813  * capture is as follows:
   1814  *
   1815  *   getReadbackBufferAttributes
   1816  *   // Readback buffer is allocated
   1817  *   // Many frames may pass
   1818  *
   1819  *   setReadbackBuffer
   1820  *   validateDisplay
   1821  *   presentDisplay
   1822  *   getReadbackBufferFence
   1823  *   // Implicitly wait on the acquire fence before accessing the buffer
   1824  *
   1825  * Parameters:
   1826  *   outFence - a sync fence file descriptor as described above; pointer
   1827  *       will be non-NULL
   1828  *
   1829  * Returns HWC2_ERROR_NONE or one of the following errors:
   1830  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1831  *   HWC2_ERROR_NO_RESOURCES - the readback operation was successful, but
   1832  *       resulted in a different validate result than would have occurred
   1833  *       without readback
   1834  *   HWC2_ERROR_UNSUPPORTED - the readback operation was unsuccessful because
   1835  *       of resource constraints, the presence of protected content, or other
   1836  *       reasons; -1 must be returned in outFence
   1837  */
   1838 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_READBACK_BUFFER_FENCE)(
   1839         hwc2_device_t* device, hwc2_display_t display,
   1840         int32_t* outFence);
   1841 
   1842 /* setReadbackBuffer(..., buffer, releaseFence)
   1843  * Optional for HWC2 devices
   1844  *
   1845  * Sets the readback buffer to be filled with the contents of the next
   1846  * composition performed for this display (i.e., the contents present at the
   1847  * time of the next validateDisplay/presentDisplay cycle).
   1848  *
   1849  * This buffer will have been allocated as described in
   1850  * getReadbackBufferAttributes and will be interpreted as being in the dataspace
   1851  * provided by the same.
   1852  *
   1853  * If there is hardware protected content on the display at the time of the next
   1854  * composition, the area of the readback buffer covered by such content must be
   1855  * completely black. Any areas of the buffer not covered by such content may
   1856  * optionally be black as well.
   1857  *
   1858  * The release fence file descriptor provided works identically to the one
   1859  * described for setOutputBuffer.
   1860  *
   1861  * This function will not be called between any call to validateDisplay and a
   1862  * subsequent call to presentDisplay.
   1863  *
   1864  * Parameters:
   1865  *   buffer - the new readback buffer
   1866  *   releaseFence - a sync fence file descriptor as described in setOutputBuffer
   1867  *
   1868  * Returns HWC2_ERROR_NONE or one of the following errors:
   1869  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1870  *   HWC2_ERROR_BAD_PARAMETER - the new readback buffer handle was invalid
   1871  *
   1872  * See also:
   1873  *   getReadbackBufferAttributes
   1874  *   getReadbackBufferFence
   1875  */
   1876 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_READBACK_BUFFER)(
   1877         hwc2_device_t* device, hwc2_display_t display,
   1878         buffer_handle_t buffer, int32_t releaseFence);
   1879 
   1880 /* setVsyncEnabled(..., enabled)
   1881  * Descriptor: HWC2_FUNCTION_SET_VSYNC_ENABLED
   1882  * Must be provided by all HWC2 devices
   1883  *
   1884  * Enables or disables the vsync signal for the given display. Virtual displays
   1885  * never generate vsync callbacks, and any attempt to enable vsync for a virtual
   1886  * display though this function must return HWC2_ERROR_NONE and have no other
   1887  * effect.
   1888  *
   1889  * Parameters:
   1890  *   enabled - whether to enable or disable vsync
   1891  *
   1892  * Returns HWC2_ERROR_NONE or one of the following errors:
   1893  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1894  *   HWC2_ERROR_BAD_PARAMETER - enabled was an invalid value
   1895  */
   1896 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_VSYNC_ENABLED)(
   1897         hwc2_device_t* device, hwc2_display_t display,
   1898         int32_t /*hwc2_vsync_t*/ enabled);
   1899 
   1900 /* validateDisplay(..., outNumTypes, outNumRequests)
   1901  * Descriptor: HWC2_FUNCTION_VALIDATE_DISPLAY
   1902  * Must be provided by all HWC2 devices
   1903  *
   1904  * Instructs the device to inspect all of the layer state and determine if
   1905  * there are any composition type changes necessary before presenting the
   1906  * display. Permitted changes are described in the definition of
   1907  * hwc2_composition_t above.
   1908  *
   1909  * Also returns the number of layer requests required
   1910  * by the given layer configuration.
   1911  *
   1912  * Parameters:
   1913  *   outNumTypes - the number of composition type changes required by the
   1914  *       device; if greater than 0, the client must either set and validate new
   1915  *       types, or call acceptDisplayChanges to accept the changes returned by
   1916  *       getChangedCompositionTypes; must be the same as the number of changes
   1917  *       returned by getChangedCompositionTypes (see the declaration of that
   1918  *       function for more information); pointer will be non-NULL
   1919  *   outNumRequests - the number of layer requests required by this layer
   1920  *       configuration; must be equal to the number of layer requests returned
   1921  *       by getDisplayRequests (see the declaration of that function for
   1922  *       more information); pointer will be non-NULL
   1923  *
   1924  * Returns HWC2_ERROR_NONE if no changes are necessary and it is safe to present
   1925  * the display using the current layer state. Otherwise returns one of the
   1926  * following errors:
   1927  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1928  *   HWC2_ERROR_HAS_CHANGES - outNumTypes was greater than 0 (see parameter list
   1929  *       for more information)
   1930  */
   1931 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_VALIDATE_DISPLAY)(
   1932         hwc2_device_t* device, hwc2_display_t display,
   1933         uint32_t* outNumTypes, uint32_t* outNumRequests);
   1934 
   1935 /*
   1936  * Layer Functions
   1937  *
   1938  * These are functions which operate on layers, but which do not modify state
   1939  * that must be validated before use. See also 'Layer State Functions' below.
   1940  *
   1941  * All of these functions take as their first three parameters a device pointer,
   1942  * a display handle for the display which contains the layer, and a layer
   1943  * handle, so these parameters are omitted from the described parameter lists.
   1944  */
   1945 
   1946 /* setCursorPosition(..., x, y)
   1947  * Descriptor: HWC2_FUNCTION_SET_CURSOR_POSITION
   1948  * Must be provided by all HWC2 devices
   1949  *
   1950  * Asynchonously sets the position of a cursor layer.
   1951  *
   1952  * Prior to validateDisplay, a layer may be marked as HWC2_COMPOSITION_CURSOR.
   1953  * If validation succeeds (i.e., the device does not request a composition
   1954  * change for that layer), then once a buffer has been set for the layer and it
   1955  * has been presented, its position may be set by this function at any time
   1956  * between presentDisplay and any subsequent validateDisplay calls for this
   1957  * display.
   1958  *
   1959  * Once validateDisplay is called, this function will not be called again until
   1960  * the validate/present sequence is completed.
   1961  *
   1962  * May be called from any thread so long as it is not interleaved with the
   1963  * validate/present sequence as described above.
   1964  *
   1965  * Parameters:
   1966  *   x - the new x coordinate (in pixels from the left of the screen)
   1967  *   y - the new y coordinate (in pixels from the top of the screen)
   1968  *
   1969  * Returns HWC2_ERROR_NONE or one of the following errors:
   1970  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   1971  *   HWC2_ERROR_BAD_LAYER - the layer is invalid or is not currently marked as
   1972  *       HWC2_COMPOSITION_CURSOR
   1973  *   HWC2_ERROR_NOT_VALIDATED - the device is currently in the middle of the
   1974  *       validate/present sequence
   1975  */
   1976 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_CURSOR_POSITION)(
   1977         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer,
   1978         int32_t x, int32_t y);
   1979 
   1980 /* setLayerBuffer(..., buffer, acquireFence)
   1981  * Descriptor: HWC2_FUNCTION_SET_LAYER_BUFFER
   1982  * Must be provided by all HWC2 devices
   1983  *
   1984  * Sets the buffer handle to be displayed for this layer. If the buffer
   1985  * properties set at allocation time (width, height, format, and usage) have not
   1986  * changed since the previous frame, it is not necessary to call validateDisplay
   1987  * before calling presentDisplay unless new state needs to be validated in the
   1988  * interim.
   1989  *
   1990  * Also provides a file descriptor referring to an acquire sync fence object,
   1991  * which will be signaled when it is safe to read from the given buffer. If it
   1992  * is already safe to read from the buffer, -1 may be passed instead. The
   1993  * device must ensure that it is safe for the client to close this file
   1994  * descriptor at any point after this function is called.
   1995  *
   1996  * This function must return HWC2_ERROR_NONE and have no other effect if called
   1997  * for a layer with a composition type of HWC2_COMPOSITION_SOLID_COLOR (because
   1998  * it has no buffer) or HWC2_COMPOSITION_SIDEBAND or HWC2_COMPOSITION_CLIENT
   1999  * (because synchronization and buffer updates for these layers are handled
   2000  * elsewhere).
   2001  *
   2002  * Parameters:
   2003  *   buffer - the buffer handle to set
   2004  *   acquireFence - a sync fence file descriptor as described above
   2005  *
   2006  * Returns HWC2_ERROR_NONE or one of the following errors:
   2007  *   HWC2_ERROR_BAD_LAYER - an invalid layer handle was passed in
   2008  *   HWC2_ERROR_BAD_PARAMETER - the buffer handle passed in was invalid
   2009  */
   2010 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_LAYER_BUFFER)(
   2011         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer,
   2012         buffer_handle_t buffer, int32_t acquireFence);
   2013 
   2014 /* setLayerSurfaceDamage(..., damage)
   2015  * Descriptor: HWC2_FUNCTION_SET_LAYER_SURFACE_DAMAGE
   2016  * Must be provided by all HWC2 devices
   2017  *
   2018  * Provides the region of the source buffer which has been modified since the
   2019  * last frame. This region does not need to be validated before calling
   2020  * presentDisplay.
   2021  *
   2022  * Once set through this function, the damage region remains the same until a
   2023  * subsequent call to this function.
   2024  *
   2025  * If damage.numRects > 0, then it may be assumed that any portion of the source
   2026  * buffer not covered by one of the rects has not been modified this frame. If
   2027  * damage.numRects == 0, then the whole source buffer must be treated as if it
   2028  * has been modified.
   2029  *
   2030  * If the layer's contents are not modified relative to the prior frame, damage
   2031  * will contain exactly one empty rect([0, 0, 0, 0]).
   2032  *
   2033  * The damage rects are relative to the pre-transformed buffer, and their origin
   2034  * is the top-left corner. They will not exceed the dimensions of the latched
   2035  * buffer.
   2036  *
   2037  * Parameters:
   2038  *   damage - the new surface damage region
   2039  *
   2040  * Returns HWC2_ERROR_NONE or one of the following errors:
   2041  *   HWC2_ERROR_BAD_LAYER - an invalid layer handle was passed in
   2042  */
   2043 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_LAYER_SURFACE_DAMAGE)(
   2044         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer,
   2045         hwc_region_t damage);
   2046 
   2047 /* setLayerPerFrameMetadata(..., numMetadata, metadata)
   2048  * Descriptor: HWC2_FUNCTION_SET_LAYER_PER_FRAME_METADATA
   2049  * Optional for HWC2 devices
   2050  *
   2051  * If supported (getFunction(HWC2_FUNCTION_SET_LAYER_PER_FRAME_METADATA) is
   2052  * non-null), sets the metadata for the given display for all following
   2053  * frames.
   2054  *
   2055  * Upon returning from this function, the metadata change must have
   2056  * fully taken effect.
   2057  *
   2058  * This function will only be called if getPerFrameMetadataKeys is non-NULL
   2059  * and returns at least one key.
   2060  *
   2061  * Parameters:
   2062  *   numElements is the number of elements in each of the keys and metadata arrays
   2063  *   keys is a pointer to the array of keys.
   2064  *   outMetadata is a pointer to the corresponding array of metadata.
   2065  *
   2066  * Returns HWC2_ERROR_NONE or one of the following errors:
   2067  *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
   2068  *   HWC2_ERROR_BAD_PARAMETER - metadata is not valid
   2069  *   HWC2_ERROR_UNSUPPORTED - metadata is not supported on this display
   2070  */
   2071 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_LAYER_PER_FRAME_METADATA)(
   2072         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer,
   2073         uint32_t numElements, const int32_t* /*hw2_per_frame_metadata_key_t*/ keys,
   2074         const float* metadata);
   2075 
   2076 /*
   2077  * Layer State Functions
   2078  *
   2079  * These functions modify the state of a given layer. They do not take effect
   2080  * until the display configuration is successfully validated with
   2081  * validateDisplay and the display contents are presented with presentDisplay.
   2082  *
   2083  * All of these functions take as their first three parameters a device pointer,
   2084  * a display handle for the display which contains the layer, and a layer
   2085  * handle, so these parameters are omitted from the described parameter lists.
   2086  */
   2087 
   2088 /* setLayerBlendMode(..., mode)
   2089  * Descriptor: HWC2_FUNCTION_SET_LAYER_BLEND_MODE
   2090  * Must be provided by all HWC2 devices
   2091  *
   2092  * Sets the blend mode of the given layer.
   2093  *
   2094  * Parameters:
   2095  *   mode - the new blend mode
   2096  *
   2097  * Returns HWC2_ERROR_NONE or one of the following errors:
   2098  *   HWC2_ERROR_BAD_LAYER - an invalid layer handle was passed in
   2099  *   HWC2_ERROR_BAD_PARAMETER - an invalid blend mode was passed in
   2100  */
   2101 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_LAYER_BLEND_MODE)(
   2102         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer,
   2103         int32_t /*hwc2_blend_mode_t*/ mode);
   2104 
   2105 /* setLayerColor(..., color)
   2106  * Descriptor: HWC2_FUNCTION_SET_LAYER_COLOR
   2107  * Must be provided by all HWC2 devices
   2108  *
   2109  * Sets the color of the given layer. If the composition type of the layer is
   2110  * not HWC2_COMPOSITION_SOLID_COLOR, this call must return HWC2_ERROR_NONE and
   2111  * have no other effect.
   2112  *
   2113  * Parameters:
   2114  *   color - the new color
   2115  *
   2116  * Returns HWC2_ERROR_NONE or one of the following errors:
   2117  *   HWC2_ERROR_BAD_LAYER - an invalid layer handle was passed in
   2118  */
   2119 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_LAYER_COLOR)(
   2120         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer,
   2121         hwc_color_t color);
   2122 
   2123 /* setLayerFloatColor(..., color)
   2124  * Descriptor: HWC2_FUNCTION_SET_LAYER_FLOAT_COLOR
   2125  * Provided by HWC2 devices which don't return nullptr function pointer.
   2126  *
   2127  * Sets the color of the given layer. If the composition type of the layer is
   2128  * not HWC2_COMPOSITION_SOLID_COLOR, this call must return HWC2_ERROR_NONE and
   2129  * have no other effect.
   2130  *
   2131  * Parameters:
   2132  *   color - the new color in float type, rage is [0.0, 1.0], the colorspace is
   2133  *   defined by the dataspace that gets set by calling setLayerDataspace.
   2134  *
   2135  * Returns HWC2_ERROR_NONE or one of the following errors:
   2136  *   HWC2_ERROR_BAD_LAYER - an invalid layer handle was passed in
   2137  */
   2138 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_LAYER_FLOAT_COLOR)(
   2139         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer,
   2140         hwc_float_color_t color);
   2141 
   2142 /* setLayerCompositionType(..., type)
   2143  * Descriptor: HWC2_FUNCTION_SET_LAYER_COMPOSITION_TYPE
   2144  * Must be provided by all HWC2 devices
   2145  *
   2146  * Sets the desired composition type of the given layer. During validateDisplay,
   2147  * the device may request changes to the composition types of any of the layers
   2148  * as described in the definition of hwc2_composition_t above.
   2149  *
   2150  * Parameters:
   2151  *   type - the new composition type
   2152  *
   2153  * Returns HWC2_ERROR_NONE or one of the following errors:
   2154  *   HWC2_ERROR_BAD_LAYER - an invalid layer handle was passed in
   2155  *   HWC2_ERROR_BAD_PARAMETER - an invalid composition type was passed in
   2156  *   HWC2_ERROR_UNSUPPORTED - a valid composition type was passed in, but it is
   2157  *       not supported by this device
   2158  */
   2159 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_LAYER_COMPOSITION_TYPE)(
   2160         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer,
   2161         int32_t /*hwc2_composition_t*/ type);
   2162 
   2163 /* setLayerDataspace(..., dataspace)
   2164  * Descriptor: HWC2_FUNCTION_SET_LAYER_DATASPACE
   2165  * Must be provided by all HWC2 devices
   2166  *
   2167  * Sets the dataspace that the current buffer on this layer is in.
   2168  *
   2169  * The dataspace provides more information about how to interpret the buffer
   2170  * contents, such as the encoding standard and color transform.
   2171  *
   2172  * See the values of android_dataspace_t in <system/graphics.h> for more
   2173  * information.
   2174  *
   2175  * Parameters:
   2176  *   dataspace - the new dataspace
   2177  *
   2178  * Returns HWC2_ERROR_NONE or one of the following errors:
   2179  *   HWC2_ERROR_BAD_LAYER - an invalid layer handle was passed in
   2180  */
   2181 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_LAYER_DATASPACE)(
   2182         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer,
   2183         int32_t /*android_dataspace_t*/ dataspace);
   2184 
   2185 /* setLayerDisplayFrame(..., frame)
   2186  * Descriptor: HWC2_FUNCTION_SET_LAYER_DISPLAY_FRAME
   2187  * Must be provided by all HWC2 devices
   2188  *
   2189  * Sets the display frame (the portion of the display covered by a layer) of the
   2190  * given layer. This frame will not exceed the display dimensions.
   2191  *
   2192  * Parameters:
   2193  *   frame - the new display frame
   2194  *
   2195  * Returns HWC2_ERROR_NONE or one of the following errors:
   2196  *   HWC2_ERROR_BAD_LAYER - an invalid layer handle was passed in
   2197  */
   2198 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_LAYER_DISPLAY_FRAME)(
   2199         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer,
   2200         hwc_rect_t frame);
   2201 
   2202 /* setLayerPlaneAlpha(..., alpha)
   2203  * Descriptor: HWC2_FUNCTION_SET_LAYER_PLANE_ALPHA
   2204  * Must be provided by all HWC2 devices
   2205  *
   2206  * Sets an alpha value (a floating point value in the range [0.0, 1.0]) which
   2207  * will be applied to the whole layer. It can be conceptualized as a
   2208  * preprocessing step which applies the following function:
   2209  *   if (blendMode == HWC2_BLEND_MODE_PREMULTIPLIED)
   2210  *       out.rgb = in.rgb * planeAlpha
   2211  *   out.a = in.a * planeAlpha
   2212  *
   2213  * If the device does not support this operation on a layer which is marked
   2214  * HWC2_COMPOSITION_DEVICE, it must request a composition type change to
   2215  * HWC2_COMPOSITION_CLIENT upon the next validateDisplay call.
   2216  *
   2217  * Parameters:
   2218  *   alpha - the plane alpha value to apply
   2219  *
   2220  * Returns HWC2_ERROR_NONE or one of the following errors:
   2221  *   HWC2_ERROR_BAD_LAYER - an invalid layer handle was passed in
   2222  */
   2223 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_LAYER_PLANE_ALPHA)(
   2224         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer,
   2225         float alpha);
   2226 
   2227 /* setLayerSidebandStream(..., stream)
   2228  * Descriptor: HWC2_FUNCTION_SET_LAYER_SIDEBAND_STREAM
   2229  * Provided by HWC2 devices which support HWC2_CAPABILITY_SIDEBAND_STREAM
   2230  *
   2231  * Sets the sideband stream for this layer. If the composition type of the given
   2232  * layer is not HWC2_COMPOSITION_SIDEBAND, this call must return HWC2_ERROR_NONE
   2233  * and have no other effect.
   2234  *
   2235  * Parameters:
   2236  *   stream - the new sideband stream
   2237  *
   2238  * Returns HWC2_ERROR_NONE or one of the following errors:
   2239  *   HWC2_ERROR_BAD_LAYER - an invalid layer handle was passed in
   2240  *   HWC2_ERROR_BAD_PARAMETER - an invalid sideband stream was passed in
   2241  */
   2242 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_LAYER_SIDEBAND_STREAM)(
   2243         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer,
   2244         const native_handle_t* stream);
   2245 
   2246 /* setLayerSourceCrop(..., crop)
   2247  * Descriptor: HWC2_FUNCTION_SET_LAYER_SOURCE_CROP
   2248  * Must be provided by all HWC2 devices
   2249  *
   2250  * Sets the source crop (the portion of the source buffer which will fill the
   2251  * display frame) of the given layer. This crop rectangle will not exceed the
   2252  * dimensions of the latched buffer.
   2253  *
   2254  * If the device is not capable of supporting a true float source crop (i.e., it
   2255  * will truncate or round the floats to integers), it should set this layer to
   2256  * HWC2_COMPOSITION_CLIENT when crop is non-integral for the most accurate
   2257  * rendering.
   2258  *
   2259  * If the device cannot support float source crops, but still wants to handle
   2260  * the layer, it should use the following code (or similar) to convert to
   2261  * an integer crop:
   2262  *   intCrop.left = (int) ceilf(crop.left);
   2263  *   intCrop.top = (int) ceilf(crop.top);
   2264  *   intCrop.right = (int) floorf(crop.right);
   2265  *   intCrop.bottom = (int) floorf(crop.bottom);
   2266  *
   2267  * Parameters:
   2268  *   crop - the new source crop
   2269  *
   2270  * Returns HWC2_ERROR_NONE or one of the following errors:
   2271  *   HWC2_ERROR_BAD_LAYER - an invalid layer handle was passed in
   2272  */
   2273 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_LAYER_SOURCE_CROP)(
   2274         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer,
   2275         hwc_frect_t crop);
   2276 
   2277 /* setLayerTransform(..., transform)
   2278  * Descriptor: HWC2_FUNCTION_SET_LAYER_TRANSFORM
   2279  * Must be provided by all HWC2 devices
   2280  *
   2281  * Sets the transform (rotation/flip) of the given layer.
   2282  *
   2283  * Parameters:
   2284  *   transform - the new transform
   2285  *
   2286  * Returns HWC2_ERROR_NONE or one of the following errors:
   2287  *   HWC2_ERROR_BAD_LAYER - an invalid layer handle was passed in
   2288  *   HWC2_ERROR_BAD_PARAMETER - an invalid transform was passed in
   2289  */
   2290 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_LAYER_TRANSFORM)(
   2291         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer,
   2292         int32_t /*hwc_transform_t*/ transform);
   2293 
   2294 /* setLayerVisibleRegion(..., visible)
   2295  * Descriptor: HWC2_FUNCTION_SET_LAYER_VISIBLE_REGION
   2296  * Must be provided by all HWC2 devices
   2297  *
   2298  * Specifies the portion of the layer that is visible, including portions under
   2299  * translucent areas of other layers. The region is in screen space, and will
   2300  * not exceed the dimensions of the screen.
   2301  *
   2302  * Parameters:
   2303  *   visible - the new visible region, in screen space
   2304  *
   2305  * Returns HWC2_ERROR_NONE or one of the following errors:
   2306  *   HWC2_ERROR_BAD_LAYER - an invalid layer handle was passed in
   2307  */
   2308 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_LAYER_VISIBLE_REGION)(
   2309         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer,
   2310         hwc_region_t visible);
   2311 
   2312 /* setLayerZOrder(..., z)
   2313  * Descriptor: HWC2_FUNCTION_SET_LAYER_Z_ORDER
   2314  * Must be provided by all HWC2 devices
   2315  *
   2316  * Sets the desired Z order (height) of the given layer. A layer with a greater
   2317  * Z value occludes a layer with a lesser Z value.
   2318  *
   2319  * Parameters:
   2320  *   z - the new Z order
   2321  *
   2322  * Returns HWC2_ERROR_NONE or one of the following errors:
   2323  *   HWC2_ERROR_BAD_LAYER - an invalid layer handle was passed in
   2324  */
   2325 typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_LAYER_Z_ORDER)(
   2326         hwc2_device_t* device, hwc2_display_t display, hwc2_layer_t layer,
   2327         uint32_t z);
   2328 
   2329 __END_DECLS
   2330 
   2331 #endif
   2332