commit 5b0ffe096f8b825ea42ff61de501fadc1d8ca418
author Brian Lindahl <blindahl@google.com> Thu Jun 15 14:19:43 2023 -0600
committer Brian Lindahl <blindahl@google.com> Thu Jun 15 20:38:55 2023 +0000
tree 0e1dbfd2b81eddd7f8a4a23411e3e960f0433e7d
parent e618e229a115d7b246773bb3fb0bf4f20c47b0b3

Force HALs to explicitly enable legacy method for clearing buffer caches

Some HAL implementations can't support setLayerBuffer multiple times to
clear the per-layer buffer caches. Therefore, default this behavior to
disabled, and allow HALs to explcitily enable this behavior to obtain
the necessary memory savings.

Test: play videos with both true and false on both HIDL and AIDL
Bug: 285561686
Change-Id: I928cef25e35cfc5337db4ceb8581bf5926b4fbe3

services/surfaceflinger/DisplayHardware/HidlComposerHal.cpp

diff --git a/services/surfaceflinger/DisplayHardware/HidlComposerHal.cpp b/services/surfaceflinger/DisplayHardware/HidlComposerHal.cpp
index e0f6c45..9b41da5 100644
--- a/services/surfaceflinger/DisplayHardware/HidlComposerHal.cpp
+++ b/services/surfaceflinger/DisplayHardware/HidlComposerHal.cpp
@@ -24,12 +24,14 @@
 
 #include "HidlComposerHal.h"
 
+#include <SurfaceFlingerProperties.h>
 #include <android/binder_manager.h>
 #include <composer-command-buffer/2.2/ComposerCommandBuffer.h>
 #include <hidl/HidlTransportSupport.h>
 #include <hidl/HidlTransportUtils.h>
 #include <log/log.h>
 #include <utils/Trace.h>
+
 #include "HWC2.h"
 #include "Hal.h"
 
@@ -189,6 +191,9 @@
 }
 
 sp<GraphicBuffer> allocateClearSlotBuffer() {
+    if (!sysprop::clear_slots_with_set_layer_buffer(false)) {
+        return nullptr;
+    }
     sp<GraphicBuffer> buffer = sp<GraphicBuffer>::make(1, 1, PIXEL_FORMAT_RGBX_8888,
                                                        GraphicBuffer::USAGE_HW_COMPOSER |
                                                                GraphicBuffer::USAGE_SW_READ_OFTEN |
@@ -246,7 +251,7 @@
         LOG_ALWAYS_FATAL("failed to create composer client");
     }
 
-    if (!mClearSlotBuffer) {
+    if (!mClearSlotBuffer && sysprop::clear_slots_with_set_layer_buffer(false)) {
         LOG_ALWAYS_FATAL("Failed to allocate a buffer for clearing layer buffer slots");
         return;
     }
@@ -716,7 +721,11 @@
     if (slotsToClear.empty()) {
         return Error::NONE;
     }
-    // Backwards compatible way of clearing buffer is to set the layer buffer with a placeholder
+    // This can be null when the HAL hasn't explicitly enabled this feature.
+    if (mClearSlotBuffer == nullptr) {
+        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