commit 50e2e4d5f75fb481b729ef05808008adad7de10a
author Dominik Laskowski <domlaskowski@google.com> Wed Oct 04 10:58:28 2023 -0400
committer Dominik Laskowski <domlaskowski@google.com> Fri Oct 06 11:29:01 2023 -0400
tree 5124e6f47f5c738feccb4047315f569aba86a615
parent cc89e85f3aa9225d977d3f78197307ec2f6f47e1

SF: Fix freezing after follower display mode set

When a mode set is initiated for any display, SF skips committing until
HWC confirms the mode set by signaling the corresponding present fence.

However, if a concurrent follower display misses a frame (i.e. does not
signal the fence) as its mode is set, SF::commit skips endlessly, since
the Scheduler only checked for missed frames on followers after commit.

Fix this by having all displays FrameTargeter::beginFrame before commit.

Fixes: 301082260
Test: Mode set on external display does not sporadically freeze SF.
Test: SchedulerTest.onFrameSignalMultipleDisplays
Change-Id: Ic97f33975f6d30279cc65cefe5d7ccc2561c45aa

services/surfaceflinger/Scheduler/Scheduler.cpp

diff --git a/services/surfaceflinger/Scheduler/Scheduler.cpp b/services/surfaceflinger/Scheduler/Scheduler.cpp
index 76f1af9..b5b20fb 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.cpp
+++ b/services/surfaceflinger/Scheduler/Scheduler.cpp
@@ -192,7 +192,8 @@
     for (const auto& [id, display] : mDisplays) {
         if (id == pacesetterId) continue;
 
-        const FrameTargeter& targeter = *display.targeterPtr;
+        FrameTargeter& targeter = *display.targeterPtr;
+        targeter.beginFrame(beginFrameArgs, *display.schedulePtr);
         targets.try_emplace(id, &targeter.target());
     }
 
@@ -206,8 +207,6 @@
         if (id == pacesetterId) continue;
 
         FrameTargeter& targeter = *display.targeterPtr;
-        targeter.beginFrame(beginFrameArgs, *display.schedulePtr);
-
         targeters.try_emplace(id, &targeter);
     }