Rewrite VirtualDisplaySurface

The previous implementation assumed that the HWC could read and write
the same buffer on frames that involved both GLES and HWC composition.
It turns out some hardware can't do this. The new implementation
maintains a scratch buffer pool to use on these mixed frames, but on
GLES-only or HWC-only frames still does composition directly into the
output buffer.

Bug: 8384764
Change-Id: I7a3addb34fad9bfcbdabbb8b635083e10223df69

1 files changed, 19 insertions, 0 deletions

diff --git a/services/surfaceflinger/DisplayDevice.cpp b/services/surfaceflinger/DisplayDevice.cpp
index 2eae9c2..c67f4d8 100644
--- a/services/surfaceflinger/DisplayDevice.cpp
+++ b/services/surfaceflinger/DisplayDevice.cpp
@@ -188,6 +188,25 @@ void DisplayDevice::flip(const Region& dirty) const
     mPageFlipCount++;
 }
 
+status_t DisplayDevice::prepareFrame(const HWComposer& hwc) const {
+    DisplaySurface::CompositionType compositionType;
+    bool haveGles = hwc.hasGlesComposition(mHwcDisplayId);
+    bool haveHwc = hwc.hasHwcComposition(mHwcDisplayId);
+    if (haveGles && haveHwc) {
+        compositionType = DisplaySurface::COMPOSITION_MIXED;
+    } else if (haveGles) {
+        compositionType = DisplaySurface::COMPOSITION_GLES;
+    } else if (haveHwc) {
+        compositionType = DisplaySurface::COMPOSITION_HWC;
+    } else {
+        // Nothing to do -- when turning the screen off we get a frame like
+        // this. Call it a HWC frame since we won't be doing any GLES work but
+        // will do a prepare/set cycle.
+        compositionType = DisplaySurface::COMPOSITION_HWC;
+    }
+    return mDisplaySurface->prepareFrame(compositionType);
+}
+
 void DisplayDevice::swapBuffers(HWComposer& hwc) const {
     // We need to call eglSwapBuffers() unless:
     // (a) there was no GLES composition this frame, or