1 page.title=Request creation and submission 2 @jd:body 3 4 <!-- 5 Copyright 2013 The Android Open Source Project 6 7 Licensed under the Apache License, Version 2.0 (the "License"); 8 you may not use this file except in compliance with the License. 9 You may obtain a copy of the License at 10 11 http://www.apache.org/licenses/LICENSE-2.0 12 13 Unless required by applicable law or agreed to in writing, software 14 distributed under the License is distributed on an "AS IS" BASIS, 15 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 16 See the License for the specific language governing permissions and 17 limitations under the License. 18 --> 19 <div id="qv-wrapper"> 20 <div id="qv"> 21 <h2>In this document</h2> 22 <ol id="auto-toc"> 23 </ol> 24 </div> 25 </div> 26 27 <h2 id="request-creation">Request creation and submission</h2> 28 <h3 id="default-settings">construct_default_request_settings</h3> 29 <p>Create capture settings for standard camera use cases. The device must return a 30 settings buffer that is configured to meet the requested use case, which must be 31 one of the CAMERA3_TEMPLATE_* enums. All request control fields must be 32 included.<br/> 33 The HAL retains ownership of this structure, but the pointer to the structure 34 must be valid until the device is closed. The framework and the HAL may not 35 modify the buffer once it is returned by this call. The same buffer may be 36 returned for subsequent calls for the same template, or for other templates.</p> 37 <h4><strong>Return values</strong></h4> 38 <ul> 39 <li>Valid metadata: On successful creation of a default settings buffer.</li> 40 <li>NULL: In case of a fatal error. After this is returned, only the close() 41 method can be called successfully by the framework.</li> 42 </ul> 43 <h3 id="process-request">process_capture_request</h3> 44 <p>Send a new capture request to the HAL. The HAL should not return from this call 45 until it is ready to accept the next request to process. Only one call to 46 process_capture_request() will be made at a time by the framework, and the calls 47 will all be from the same thread. The next call to process_capture_request() 48 will be made as soon as a new request and its associated buffers are available. 49 In a normal preview scenario, this means the function will be called again by 50 the framework almost instantly.<br/> 51 The actual request processing is asynchronous, with the results of capture being 52 returned by the HAL through the process_capture_result() call. This call 53 requires the result metadata to be available, but output buffers may simply 54 provide sync fences to wait on. Multiple requests are expected to be in flight 55 at once, to maintain full output frame rate.<br/> 56 The framework retains ownership of the request structure. It is only guaranteed 57 to be valid during this call. The HAL device must make copies of the information 58 it needs to retain for the capture processing. The HAL is responsible for 59 waiting on and closing the buffers' fences and returning the buffer handles to 60 the framework.<br/> 61 The HAL must write the file descriptor for the input buffer's release sync fence 62 into input_buffer->release_fence, if input_buffer is not NULL. If the HAL 63 returns -1 for the input buffer release sync fence, the framework is free to 64 immediately reuse the input buffer. Otherwise, the framework will wait on the 65 sync fence before refilling and reusing the input buffer.</p> 66 <h4><strong>Return values</strong></h4> 67 <ul> 68 <li>0: On a successful start to processing the capture request</li> 69 <li>-EINVAL: If the input is malformed (the settings are NULL when not allowed, 70 there are 0 output buffers, etc) and capture processing cannot start. Failures 71 during request processing should be handled by calling 72 camera3_callback_ops_t.notify(). In case of this error, the framework will 73 retain responsibility for the stream buffers' fences and the buffer handles; 74 the HAL should not close the fences or return these buffers with 75 process_capture_result.</li> 76 <li>-ENODEV: If the camera device has encountered a serious error. After this 77 error is returned, only the close() method can be successfully called by the 78 framework.</li> 79 </ul> 80 <h2 id="misc-methods">Miscellaneous methods</h2> 81 <h3 id="get-metadata">get_metadata_vendor_tag_ops</h3> 82 <p>Get methods to query for vendor extension metadata tag information. The HAL 83 should fill in all the vendor tag operation methods, or leave ops unchanged if 84 no vendor tags are defined. The definition of vendor_tag_query_ops_t can be 85 found in system/media/camera/include/system/camera_metadata.h.</p> 86 <h3 id="dump">dump</h3> 87 <p>Print out debugging state for the camera device. This will be called by the 88 framework when the camera service is asked for a debug dump, which happens when 89 using the dumpsys tool, or when capturing a bugreport. The passed-in file 90 descriptor can be used to write debugging text using dprintf() or write(). The 91 text should be in ASCII encoding only.</p> 92 <h3 id="flush">flush</h3> 93 <p>Flush all currently in-process captures and all buffers in the pipeline on the 94 given device. The framework will use this to dump all state as quickly as 95 possible in order to prepare for a configure_streams() call.<br/> 96 No buffers are required to be successfully returned, so every buffer held at the 97 time of flush() (whether successfully filled or not) may be returned with 98 CAMERA3_BUFFER_STATUS_ERROR. Note the HAL is still allowed to return valid 99 (STATUS_OK) buffers during this call, provided they are successfully filled.<br/> 100 All requests currently in the HAL are expected to be returned as soon as 101 possible. Not-in-process requests should return errors immediately. Any 102 interruptible hardware blocks should be stopped, and any uninterruptible blocks 103 should be waited on.<br/> 104 flush() should only return when there are no more outstanding buffers or 105 requests left in the HAL. The framework may call configure_streams (as the HAL 106 state is now quiesced) or may issue new requests.<br/> 107 A flush() call should only take 100ms or less. The maximum time it can take is 1 108 second.</p> 109 <h4><strong>Version information</strong></h4> 110 <p>This is available only if device version >= CAMERA_DEVICE_API_VERSION_3_1.</p> 111 <h4><strong>Return values</strong></h4> 112 <ul> 113 <li>0: On a successful flush of the camera HAL.</li> 114 <li>-EINVAL: If the input is malformed (the device is not valid).</li> 115 <li>-ENODEV: If the camera device has encountered a serious error. After this 116 error is returned, only the close() method can be successfully called by the 117 framework.</li> 118 </ul> 119
