commit 1e27ba234c5bfd4f6535ee221a6c20407a50f868
author Jesse Hall <jessehall@google.com> Fri Sep 27 09:05:09 2013 -0700
committer Jesse Hall <jessehall@google.com> Thu Oct 17 11:20:22 2013 -0700
tree 3edb31d034068841b0fb6541bb36f4d4b53fe24f
parent dacd4159631865da1a02203fe5fa7c5f1339cda9

Use implementation-defined format when HWC writes to output buffer

When GLES isn't writing to the output buffer directly, request an
implementation-defined format with minimal usage flags, leaving the
format choice up to gralloc. On some hardware this allows HWC to do
format conversions during composition that would otherwise need to be
done (with worse power and/or performance) by the consumer.

Bug: 8316155
Change-Id: Iee6ee8404282036f9fd1833067cfe11dbadbf0bf

services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp

diff --git a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp
index c5a14b0..29e9d40 100644
--- a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp
+++ b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp
@@ -47,7 +47,8 @@
     mHwc(hwc),
     mDisplayId(dispId),
     mDisplayName(name),
-    mProducerUsage(GRALLOC_USAGE_HW_COMPOSER),
+    mOutputFormat(HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED),
+    mOutputUsage(GRALLOC_USAGE_HW_COMPOSER),
     mProducerSlotSource(0),
     mDbgState(DBG_STATE_IDLE),
     mDbgLastCompositionType(COMPOSITION_UNKNOWN)
@@ -95,13 +96,30 @@
     mDbgState = DBG_STATE_PREPARED;
 
     mCompositionType = compositionType;
-
     if (mCompositionType != mDbgLastCompositionType) {
         VDS_LOGV("prepareFrame: composition type changed to %s",
                 dbgCompositionTypeStr(mCompositionType));
         mDbgLastCompositionType = mCompositionType;
     }
 
+    if (mCompositionType != COMPOSITION_GLES &&
+            (mOutputFormat != HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED ||
+             mOutputUsage != GRALLOC_USAGE_HW_COMPOSER)) {
+        // We must have just switched from GLES-only to MIXED or HWC
+        // composition. Stop using the format and usage requested by the GLES
+        // driver; they may be suboptimal when HWC is writing to the output
+        // buffer. For example, if the output is going to a video encoder, and
+        // HWC can write directly to YUV, some hardware can skip a
+        // memory-to-memory RGB-to-YUV conversion step.
+        //
+        // If we just switched *to* GLES-only mode, we'll change the
+        // format/usage and get a new buffer when the GLES driver calls
+        // dequeueBuffer().
+        mOutputFormat = HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED;
+        mOutputUsage = GRALLOC_USAGE_HW_COMPOSER;
+        refreshOutputBuffer();
+    }
+
     return NO_ERROR;
 }
 
@@ -212,12 +230,12 @@
 }
 
 status_t VirtualDisplaySurface::dequeueBuffer(Source source,
-        uint32_t format, int* sslot, sp<Fence>* fence) {
+        uint32_t format, uint32_t usage, int* sslot, sp<Fence>* fence) {
     // Don't let a slow consumer block us
     bool async = (source == SOURCE_SINK);
 
     status_t result = mSource[source]->dequeueBuffer(sslot, fence, async,
-            mSinkBufferWidth, mSinkBufferHeight, format, mProducerUsage);
+            mSinkBufferWidth, mSinkBufferHeight, format, usage);
     if (result < 0)
         return result;
     int pslot = mapSource2ProducerSlot(source, *sslot);
@@ -258,7 +276,6 @@
     VDS_LOGV("dequeueBuffer %dx%d fmt=%d usage=%#x", w, h, format, usage);
 
     status_t result = NO_ERROR;
-    mProducerUsage = usage | GRALLOC_USAGE_HW_COMPOSER;
     Source source = fbSourceForCompositionType(mCompositionType);
 
     if (source == SOURCE_SINK) {
@@ -279,13 +296,20 @@
         // prepare and set, but since we're in GLES-only mode already it
         // shouldn't matter.
 
+        usage |= GRALLOC_USAGE_HW_COMPOSER;
         const sp<GraphicBuffer>& buf = mProducerBuffers[mOutputProducerSlot];
-        if ((mProducerUsage & ~buf->getUsage()) != 0 ||
+        if ((usage & ~buf->getUsage()) != 0 ||
                 (format != 0 && format != (uint32_t)buf->getPixelFormat()) ||
                 (w != 0 && w != mSinkBufferWidth) ||
                 (h != 0 && h != mSinkBufferHeight)) {
-            VDS_LOGV("dequeueBuffer: output buffer doesn't satisfy GLES "
-                    "request, getting a new buffer");
+            VDS_LOGV("dequeueBuffer: dequeueing new output buffer: "
+                    "want %dx%d fmt=%d use=%#x, "
+                    "have %dx%d fmt=%d use=%#x",
+                    w, h, format, usage,
+                    mSinkBufferWidth, mSinkBufferHeight,
+                    buf->getPixelFormat(), buf->getUsage());
+            mOutputFormat = format;
+            mOutputUsage = usage;
             result = refreshOutputBuffer();
             if (result < 0)
                 return result;
@@ -297,7 +321,7 @@
         *fence = mOutputFence;
     } else {
         int sslot;
-        result = dequeueBuffer(source, format, &sslot, fence);
+        result = dequeueBuffer(source, format, usage, &sslot, fence);
         if (result >= 0) {
             *pslot = mapSource2ProducerSlot(source, sslot);
         }
@@ -414,7 +438,8 @@
     }
 
     int sslot;
-    status_t result = dequeueBuffer(SOURCE_SINK, 0, &sslot, &mOutputFence);
+    status_t result = dequeueBuffer(SOURCE_SINK, mOutputFormat, mOutputUsage,
+            &sslot, &mOutputFence);
     if (result < 0)
         return result;
     mOutputProducerSlot = mapSource2ProducerSlot(SOURCE_SINK, sslot);