commit a13f2d58e01d980d39d3617032120c5f9b6423bd
author Brian Lindahl <blindahl@google.com> Thu Mar 05 11:54:17 2020 +0100
committer Brian Lindahl <blindahl@google.com> Mon Mar 09 07:50:20 2020 +0000
tree 612cc7ac616b97c4dbb7d0ffc01787de569db840
parent a821321b901c5fdd9d00914ad3dbfbfa07f78695

Allow GPU composition to occur at a lower resolution

Add a vendor-specified system property to allow GPU fallback composition to occur at a lower resolution than the display mode resolution.

Bug: 144574809

Test: Tested with sysprop disabled, and tested backport in Android Q with sysprop enabled. Unable to test on Android R due to device issues.

Change-Id: I02948ce72f49d20416d0e4dd45a4cffe99e28820

services/surfaceflinger/DisplayHardware/FramebufferSurface.cpp

diff --git a/services/surfaceflinger/DisplayHardware/FramebufferSurface.cpp b/services/surfaceflinger/DisplayHardware/FramebufferSurface.cpp
index 36544b6..aeffb0e 100644
--- a/services/surfaceflinger/DisplayHardware/FramebufferSurface.cpp
+++ b/services/surfaceflinger/DisplayHardware/FramebufferSurface.cpp
@@ -57,9 +57,12 @@
  */
 
 FramebufferSurface::FramebufferSurface(HWComposer& hwc, DisplayId displayId,
-                                       const sp<IGraphicBufferConsumer>& consumer)
+                                       const sp<IGraphicBufferConsumer>& consumer,
+                                       uint32_t maxWidth, uint32_t maxHeight)
       : ConsumerBase(consumer),
         mDisplayId(displayId),
+        mMaxWidth(maxWidth),
+        mMaxHeight(maxHeight),
         mCurrentBufferSlot(-1),
         mCurrentBuffer(),
         mCurrentFence(Fence::NO_FENCE),
@@ -75,14 +78,16 @@
                                        GRALLOC_USAGE_HW_RENDER |
                                        GRALLOC_USAGE_HW_COMPOSER);
     const auto& activeConfig = mHwc.getActiveConfig(displayId);
-    mConsumer->setDefaultBufferSize(activeConfig->getWidth(),
-            activeConfig->getHeight());
+    ui::Size limitedSize =
+            limitFramebufferSize(activeConfig->getWidth(), activeConfig->getHeight());
+    mConsumer->setDefaultBufferSize(limitedSize.width, limitedSize.height);
     mConsumer->setMaxAcquiredBufferCount(
             SurfaceFlinger::maxFrameBufferAcquiredBuffers - 1);
 }
 
-void FramebufferSurface::resizeBuffers(const uint32_t width, const uint32_t height) {
-    mConsumer->setDefaultBufferSize(width, height);
+void FramebufferSurface::resizeBuffers(uint32_t width, uint32_t height) {
+    ui::Size limitedSize = limitFramebufferSize(width, height);
+    mConsumer->setDefaultBufferSize(limitedSize.width, limitedSize.height);
 }
 
 status_t FramebufferSurface::beginFrame(bool /*mustRecompose*/) {
@@ -177,6 +182,29 @@
     }
 }
 
+ui::Size FramebufferSurface::limitFramebufferSize(uint32_t width, uint32_t height) {
+    // TODO(b/149495759): Use the ui::Size constructor once it no longer is broken.
+    ui::Size framebufferSize;
+    framebufferSize.width = width;
+    framebufferSize.height = height;
+    bool wasLimited = true;
+    if (width > mMaxWidth && mMaxWidth != 0) {
+        float aspectRatio = float(width) / float(height);
+        framebufferSize.height = mMaxWidth / aspectRatio;
+        framebufferSize.width = mMaxWidth;
+        wasLimited = true;
+    }
+    if (height > mMaxHeight && mMaxHeight != 0) {
+        float aspectRatio = float(width) / float(height);
+        framebufferSize.height = mMaxHeight;
+        framebufferSize.width = mMaxHeight * aspectRatio;
+        wasLimited = true;
+    }
+    ALOGI_IF(wasLimited, "framebuffer size has been limited to [%dx%d] from [%dx%d]",
+             framebufferSize.width, framebufferSize.height, width, height);
+    return framebufferSize;
+}
+
 void FramebufferSurface::dumpAsString(String8& result) const {
     Mutex::Autolock lock(mMutex);
     result.appendFormat("  FramebufferSurface: dataspace: %s(%d)\n",