commit 0ea47b50a6f37e703390e0ac6b8e36d98187a2c8
author Sally Qi <sallyqi@google.com> Thu Jun 22 13:27:20 2023 -0700
committer Sally Qi <sallyqi@google.com> Fri Jun 23 19:02:09 2023 +0000
tree 7267e2794e00df6dc75946d5609e1d49f7b96541
parent f0049a0421e3b2077a533800d170d5817ef059a5

Optimize the way of calling setDisplayBrightness.

 - Only call it when display brightness difference ratio is over than
   threshold.

Bug: 267262025
Test: play with Youtube HDR video
Change-Id: I24cf0f01db342711d6b2a160b384c006c44fdad4

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 3165b9e..a97b5e4 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1830,8 +1830,21 @@
                        float currentDimmingRatio =
                                compositionDisplay->editState().sdrWhitePointNits /
                                compositionDisplay->editState().displayBrightnessNits;
-                       compositionDisplay->setDisplayBrightness(brightness.sdrWhitePointNits,
-                                                                brightness.displayBrightnessNits);
+                       static constexpr float kDimmingThreshold = 0.02f;
+                       if (brightness.sdrWhitePointNits == 0.f ||
+                           abs(brightness.sdrWhitePointNits - brightness.displayBrightnessNits) /
+                                           brightness.sdrWhitePointNits >=
+                                   kDimmingThreshold) {
+                           // to optimize, skip brightness setter if the brightness difference ratio
+                           // is lower than threshold
+                           compositionDisplay
+                                   ->setDisplayBrightness(brightness.sdrWhitePointNits,
+                                                          brightness.displayBrightnessNits);
+                       } else {
+                           compositionDisplay->setDisplayBrightness(brightness.sdrWhitePointNits,
+                                                                    brightness.sdrWhitePointNits);
+                       }
+
                        FTL_FAKE_GUARD(kMainThreadContext,
                                       display->stageBrightness(brightness.displayBrightness));