commit 993ddf4afb45b389e950a16237de720783fad485
author Marin Shalamanov <shalamanov@google.com> Wed May 26 16:54:40 2021 +0200
committer Marin Shalamanov <shalamanov@google.com> Mon Jun 14 10:46:56 2021 +0200
tree 6e84763d873daf8304d51c8e662977600b386e6f
parent c2baccc476ad91b538e84e3f4379a66f237ee07b

SF: Recreate display on resolution changes

When the resolution changes from SurfaceFlinger we
need to recreate the frambuffer. This CL reuses the
existing mechanism for processing display changes
to do that. More specifically the logic in this CL
does the same as if there was a subsequent hotplug
"connected" event.

This removes the need HWC HAL implementations to
send hotplug events on each resolution change
(which was violating VTS).

This change impacts only devices which support
multiple resolutions (e.g. TV but no phones).

Test: atest DisplayTest SetFrameRateTest
Test: plug hdmi out and in and verify that there are
      no crashes
Bug: 188684566
Change-Id: I8a00657e9eeb1db716ce58aac7b3e3e40f898352

services/surfaceflinger/Scheduler/RefreshRateStats.h

diff --git a/services/surfaceflinger/Scheduler/RefreshRateStats.h b/services/surfaceflinger/Scheduler/RefreshRateStats.h
index 80f4665..208a767 100644
--- a/services/surfaceflinger/Scheduler/RefreshRateStats.h
+++ b/services/surfaceflinger/Scheduler/RefreshRateStats.h
@@ -61,6 +61,7 @@
         if (mCurrentRefreshRate.equalsWithMargin(currRefreshRate)) {
             return;
         }
+        mTimeStats.incrementRefreshRateSwitches();
         flushTime();
         mCurrentRefreshRate = currRefreshRate;
     }

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index a4b6fef..31c1222 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1139,7 +1139,18 @@
         // have been already updated with the upcoming active mode.
         return;
     }
-    const Fps oldRefreshRate = display->getActiveMode()->getFps();
+
+    if (display->getActiveMode()->getSize() != upcomingMode->getSize()) {
+        auto& state = mCurrentState.displays.editValueFor(display->getDisplayToken());
+        // We need to generate new sequenceId in order to recreate the display (and this
+        // way the framebuffer).
+        state.sequenceId = DisplayDeviceState{}.sequenceId;
+        state.physical->activeMode = upcomingMode;
+        processDisplayChangesLocked();
+
+        // processDisplayChangesLocked will update all necessary components so we're done here.
+        return;
+    }
 
     std::lock_guard<std::mutex> lock(mActiveModeLock);
     mRefreshRateConfigs->setCurrentModeId(mUpcomingActiveMode.modeId);
@@ -1149,9 +1160,6 @@
 
     mRefreshRateStats->setRefreshRate(refreshRate);
 
-    if (!refreshRate.equalsWithMargin(oldRefreshRate)) {
-        mTimeStats->incrementRefreshRateSwitches();
-    }
     updatePhaseConfiguration(refreshRate);
     ATRACE_INT("ActiveConfigFPS", refreshRate.getValue());
 
@@ -2808,7 +2816,10 @@
                 mRefreshRateConfigs->updateDisplayModes(currentState.physical->supportedModes,
                                                         currentState.physical->activeMode->getId());
                 mVsyncConfiguration->reset();
-                updatePhaseConfiguration(mRefreshRateConfigs->getCurrentRefreshRate().getFps());
+                const Fps refreshRate = currentState.physical->activeMode->getFps();
+                updatePhaseConfiguration(refreshRate);
+                mRefreshRateStats->setRefreshRate(refreshRate);
+
                 if (mRefreshRateOverlay) {
                     mRefreshRateOverlay->reset();
                 }