commit 5690bde1e9192bc161ff6ae9fc80d8c4eaef6fd9
author Dominik Laskowski <domlaskowski@google.com> Thu Apr 23 19:04:22 2020 -0700
committer Dominik Laskowski <domlaskowski@google.com> Mon Apr 27 17:41:27 2020 -0700
tree 840c4ce1c5d00b75aa9a8a478ba580a7740f193b
parent 8e89c2ad0f2981f196307285d7d45b42c17356e4

SF: Defer setDisplayBrightness to Binder thread

setDisplayBrightness blocks for a long time so cannot run on the main
thread. Keep display lookup on the main thread, but return a deferred
future to the Binder thread and run it there.

Bug: 154202427
Bug: 123715322
Test: systrace with backdoor to set brightness
Change-Id: I88e60c95db5fdcaa1bf5ebb9711e3bf5ab6539a1

services/surfaceflinger/DisplayHardware/HWC2.cpp

diff --git a/services/surfaceflinger/DisplayHardware/HWC2.cpp b/services/surfaceflinger/DisplayHardware/HWC2.cpp
index d6dbd57..0ea3340 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWC2.cpp
@@ -25,7 +25,6 @@
 #define ATRACE_TAG ATRACE_TAG_GRAPHICS
 
 #include "HWC2.h"
-#include "ComposerHal.h"
 
 #include <ui/Fence.h>
 #include <ui/FloatRect.h>
@@ -38,6 +37,9 @@
 #include <iterator>
 #include <set>
 
+#include "../Promise.h"
+#include "ComposerHal.h"
+
 namespace android {
 
 using android::Fence;
@@ -640,12 +642,14 @@
     return error;
 }
 
-Error Display::setDisplayBrightness(float brightness) const {
-    const auto intError = mComposer.setDisplayBrightness(mId, brightness);
-    return static_cast<Error>(intError);
+std::future<Error> Display::setDisplayBrightness(float brightness) {
+    return promise::defer([composer = &mComposer, id = mId, brightness] {
+        const auto intError = composer->setDisplayBrightness(id, brightness);
+        return static_cast<Error>(intError);
+    });
 }
 
-Error Display::setAutoLowLatencyMode(bool on) const {
+Error Display::setAutoLowLatencyMode(bool on) {
     auto intError = mComposer.setAutoLowLatencyMode(mId, on);
     return static_cast<Error>(intError);
 }
@@ -659,7 +663,7 @@
     return static_cast<Error>(intError);
 }
 
-Error Display::setContentType(ContentType contentType) const {
+Error Display::setContentType(ContentType contentType) {
     auto intError = mComposer.setContentType(mId, contentType);
     return static_cast<Error>(intError);
 }