commit 5d22d4ff67152296d54e9ce19f67fd9fff328724
author Michael Wright <michaelwr@google.com> Thu Jun 21 02:50:34 2018 +0100
committer Peiyong Lin <lpy@google.com> Mon Jun 25 19:54:22 2018 -0700
tree a08f91f83133b3f4653a8fce0a4a08245ac7b63c
parent 93a9ec16aafb00e5331228a506835e77a953a207

Add new PowerAdvisor interface for SF to pass hints to the power HAL.

GPU composition is slow with FP16 wide color gamut. In this patch, we try to
mitigate this issue by boosting the GPU to higher frequency when SurfaceFlinger
is going to switch to Display P3 color mode by sending the new
PowerHint::EXPENSIVE_RENDERING to PowerManager.

BUG: 110112323
Test: adb shell cat /sys/class/kgsl/kgsl-3d0/devfreq/cur_freq to verify GPU
      frequency with/without WCG content. GPU frequency should be high with
      WCG content, and should be reset without WCG content.
Change-Id: I3758bcf9940e71d4b6d122d8916b7ad7f10f5397

services/surfaceflinger/DisplayHardware/HWC2.cpp

diff --git a/services/surfaceflinger/DisplayHardware/HWC2.cpp b/services/surfaceflinger/DisplayHardware/HWC2.cpp
index 9546c86..add93fd 100644
--- a/services/surfaceflinger/DisplayHardware/HWC2.cpp
+++ b/services/surfaceflinger/DisplayHardware/HWC2.cpp
@@ -144,7 +144,7 @@
     }
 
     auto display = std::make_unique<Display>(
-            *mComposer.get(), mCapabilities, displayId, DisplayType::Virtual);
+            *mComposer.get(), mPowerAdvisor, mCapabilities, displayId, DisplayType::Virtual);
     display->setConnected(true);
     *outDisplay = display.get();
     mDisplays.emplace(displayId, std::move(display));
@@ -183,7 +183,7 @@
         }
 
         auto newDisplay = std::make_unique<Display>(
-                *mComposer.get(), mCapabilities, displayId, displayType);
+                *mComposer.get(), mPowerAdvisor, mCapabilities, displayId, displayType);
         newDisplay->setConnected(true);
         mDisplays.emplace(displayId, std::move(newDisplay));
     } else if (connection == Connection::Disconnected) {
@@ -225,10 +225,11 @@
 
 // Display methods
 
-Display::Display(android::Hwc2::Composer& composer,
+Display::Display(android::Hwc2::Composer& composer, android::Hwc2::PowerAdvisor& advisor,
                  const std::unordered_set<Capability>& capabilities, hwc2_display_t id,
                  DisplayType type)
       : mComposer(composer),
+        mPowerAdvisor(advisor),
         mCapabilities(capabilities),
         mId(id),
         mIsConnected(false),
@@ -611,6 +612,12 @@
 
 Error Display::setColorMode(ColorMode mode, RenderIntent renderIntent)
 {
+    // When the color mode is switched to DISPLAY_P3, we want to boost the GPU frequency
+    // so that GPU composition can finish in time. When color mode is switched from
+    // DISPLAY_P3, we want to reset GPU frequency.
+    const bool expensiveRenderingExpected = (mode == ColorMode::DISPLAY_P3);
+    mPowerAdvisor.setExpensiveRenderingExpected(mId, expensiveRenderingExpected);
+
     auto intError = mComposer.setColorMode(mId, mode, renderIntent);
     return static_cast<Error>(intError);
 }