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      1 /*
      2  * Copyright (C) 2012 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 #define ATRACE_TAG ATRACE_TAG_GRAPHICS
     18 //#define LOG_NDEBUG 0
     19 
     20 #include "SurfaceFlingerConsumer.h"
     21 
     22 #include <private/gui/SyncFeatures.h>
     23 
     24 #include <utils/Trace.h>
     25 #include <utils/Errors.h>
     26 
     27 namespace android {
     28 
     29 // ---------------------------------------------------------------------------
     30 
     31 status_t SurfaceFlingerConsumer::updateTexImage(BufferRejecter* rejecter)
     32 {
     33     ATRACE_CALL();
     34     ALOGV("updateTexImage");
     35     Mutex::Autolock lock(mMutex);
     36 
     37     if (mAbandoned) {
     38         ALOGE("updateTexImage: GLConsumer is abandoned!");
     39         return NO_INIT;
     40     }
     41 
     42     // Make sure the EGL state is the same as in previous calls.
     43     status_t err = checkAndUpdateEglStateLocked();
     44     if (err != NO_ERROR) {
     45         return err;
     46     }
     47 
     48     BufferQueue::BufferItem item;
     49 
     50     // Acquire the next buffer.
     51     // In asynchronous mode the list is guaranteed to be one buffer
     52     // deep, while in synchronous mode we use the oldest buffer.
     53     err = acquireBufferLocked(&item, computeExpectedPresent());
     54     if (err != NO_ERROR) {
     55         if (err == BufferQueue::NO_BUFFER_AVAILABLE) {
     56             err = NO_ERROR;
     57         } else if (err == BufferQueue::PRESENT_LATER) {
     58             // return the error, without logging
     59         } else {
     60             ALOGE("updateTexImage: acquire failed: %s (%d)",
     61                 strerror(-err), err);
     62         }
     63         return err;
     64     }
     65 
     66 
     67     // We call the rejecter here, in case the caller has a reason to
     68     // not accept this buffer.  This is used by SurfaceFlinger to
     69     // reject buffers which have the wrong size
     70     int buf = item.mBuf;
     71     if (rejecter && rejecter->reject(mSlots[buf].mGraphicBuffer, item)) {
     72         releaseBufferLocked(buf, mSlots[buf].mGraphicBuffer, EGL_NO_SYNC_KHR);
     73         return NO_ERROR;
     74     }
     75 
     76     // Release the previous buffer.
     77     err = updateAndReleaseLocked(item);
     78     if (err != NO_ERROR) {
     79         return err;
     80     }
     81 
     82     if (!SyncFeatures::getInstance().useNativeFenceSync()) {
     83         // Bind the new buffer to the GL texture.
     84         //
     85         // Older devices require the "implicit" synchronization provided
     86         // by glEGLImageTargetTexture2DOES, which this method calls.  Newer
     87         // devices will either call this in Layer::onDraw, or (if it's not
     88         // a GL-composited layer) not at all.
     89         err = bindTextureImageLocked();
     90     }
     91 
     92     return err;
     93 }
     94 
     95 status_t SurfaceFlingerConsumer::bindTextureImage()
     96 {
     97     Mutex::Autolock lock(mMutex);
     98 
     99     return bindTextureImageLocked();
    100 }
    101 
    102 status_t SurfaceFlingerConsumer::acquireBufferLocked(
    103         BufferQueue::BufferItem *item, nsecs_t presentWhen) {
    104     status_t result = GLConsumer::acquireBufferLocked(item, presentWhen);
    105     if (result == NO_ERROR) {
    106         mTransformToDisplayInverse = item->mTransformToDisplayInverse;
    107     }
    108     return result;
    109 }
    110 
    111 bool SurfaceFlingerConsumer::getTransformToDisplayInverse() const {
    112     return mTransformToDisplayInverse;
    113 }
    114 
    115 // We need to determine the time when a buffer acquired now will be
    116 // displayed.  This can be calculated:
    117 //   time when previous buffer's actual-present fence was signaled
    118 //    + current display refresh rate * HWC latency
    119 //    + a little extra padding
    120 //
    121 // Buffer producers are expected to set their desired presentation time
    122 // based on choreographer time stamps, which (coming from vsync events)
    123 // will be slightly later then the actual-present timing.  If we get a
    124 // desired-present time that is unintentionally a hair after the next
    125 // vsync, we'll hold the frame when we really want to display it.  We
    126 // want to use an expected-presentation time that is slightly late to
    127 // avoid this sort of edge case.
    128 nsecs_t SurfaceFlingerConsumer::computeExpectedPresent()
    129 {
    130     // Don't yet have an easy way to get actual buffer flip time for
    131     // the specific display, so use the current time.  This is typically
    132     // 1.3ms past the vsync event time.
    133     const nsecs_t prevVsync = systemTime(CLOCK_MONOTONIC);
    134 
    135     // Given a SurfaceFlinger reference, and information about what display
    136     // we're destined for, we could query the HWC for the refresh rate.  This
    137     // could change over time, e.g. we could switch to 24fps for a movie.
    138     // For now, assume 60fps.
    139     //const nsecs_t vsyncPeriod =
    140     //        getHwComposer().getRefreshPeriod(HWC_DISPLAY_PRIMARY);
    141     const nsecs_t vsyncPeriod = 16700000;
    142 
    143     // The HWC doesn't currently have a way to report additional latency.
    144     // Assume that whatever we submit now will appear on the next flip,
    145     // i.e. 1 frame of latency w.r.t. the previous flip.
    146     const uint32_t hwcLatency = 1;
    147 
    148     // A little extra padding to compensate for slack between actual vsync
    149     // time and vsync event receipt.  Currently not needed since we're
    150     // using "now" instead of a vsync time.
    151     const nsecs_t extraPadding = 0;
    152 
    153     // Total it up.
    154     return prevVsync + hwcLatency * vsyncPeriod + extraPadding;
    155 }
    156 
    157 // ---------------------------------------------------------------------------
    158 }; // namespace android
    159 
    160