Maintain the active buffer when clearing buffer slots
When an app discards graphic buffers, for example when a MediaCodec
disconnects from a surface, those buffers will be uncached and removed
from HWC buffer slots. The active buffer, however, should still remain
active until the next buffer is queued up.
Bug: 262037933
Bug: 258196272
Test: atest OutputLayerUncacheBufferTest
Test: atest VtsHalGraphicsComposer3_TargetTest
Test: atest VtsHalGraphicsComposerV2_2TargetTest
Change-Id: I7c4eefb17e8bad694d698f9ad6d1d289f4af8d2c
diff --git a/services/surfaceflinger/DisplayHardware/HidlComposerHal.cpp b/services/surfaceflinger/DisplayHardware/HidlComposerHal.cpp
index 9a49d94..c9e1e79 100644
--- a/services/surfaceflinger/DisplayHardware/HidlComposerHal.cpp
+++ b/services/surfaceflinger/DisplayHardware/HidlComposerHal.cpp
@@ -712,10 +712,29 @@
return Error::NONE;
}
-Error HidlComposer::clearLayerBufferSlot(Display display, Layer layer, uint32_t slot) {
+Error HidlComposer::setLayerBufferSlotsToClear(Display display, Layer layer,
+ const std::vector<uint32_t>& slotsToClear,
+ uint32_t activeBufferSlot) {
+ if (slotsToClear.empty()) {
+ return Error::NONE;
+ }
+ // Backwards compatible way of clearing buffer is to set the layer buffer with a placeholder
+ // buffer, using the slot that needs to cleared... tricky.
+ for (uint32_t slot : slotsToClear) {
+ // Don't clear the active buffer slot because we need to restore the active buffer after
+ // setting the requested buffer slots with a placeholder buffer.
+ if (slot != activeBufferSlot) {
+ mWriter.selectDisplay(display);
+ mWriter.selectLayer(layer);
+ mWriter.setLayerBuffer(slot, mClearSlotBuffer->handle, /*fence*/ -1);
+ }
+ }
+ // Since we clear buffers by setting them to a placeholder buffer, we want to make sure that the
+ // last setLayerBuffer command is sent with the currently active buffer, not the placeholder
+ // buffer, so that there is no perceptual change.
mWriter.selectDisplay(display);
mWriter.selectLayer(layer);
- mWriter.setLayerBuffer(slot, mClearSlotBuffer->handle, /*fence*/ -1);
+ mWriter.setLayerBuffer(activeBufferSlot, /*buffer*/ nullptr, /*fence*/ -1);
return Error::NONE;
}