commit 575aa7232035b8da3336ee5170e8016bd16460ae
author Dominik Laskowski <domlaskowski@google.com> Mon Jun 17 11:03:30 2024 -0400
committer Android Build Coastguard Worker <android-build-coastguard-worker@google.com> Fri Jun 21 23:22:49 2024 +0000
tree 7202908f8dd55b2f82067d41506d0be3f8491901
parent 00299f508bdd94873514f55df0821c842e48abb1

SF: Fix pacesetter promotion for folded mirroring

The pacesetter display is demoted/promoted in response to a hotplug. On
foldables, the promoted display was hard-coded to the inner display, so
a hotplug while folded would incorrectly use that powered-off display as
the pacesetter, causing system-wide jank until the next fold/unfold.

Fixes: 347248313
Flag: EXEMPT bugfix
Test: Connect and disconnect external display while folded.
Test: Fold and unfold while external display is connected.
Test: Pacesetter is still correct on folded/unfolded boot.
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:3ff44c7e852f5614514a15dcec78ba7857e5d010)
Merged-In: Id5cb29c3cbaa8ed455a15d8be3a32e79a470cce5
Change-Id: Id5cb29c3cbaa8ed455a15d8be3a32e79a470cce5

services/surfaceflinger/Scheduler/Scheduler.cpp

diff --git a/services/surfaceflinger/Scheduler/Scheduler.cpp b/services/surfaceflinger/Scheduler/Scheduler.cpp
index 60681a2..26e11e5 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.cpp
+++ b/services/surfaceflinger/Scheduler/Scheduler.cpp
@@ -123,19 +123,22 @@
     promotePacesetterDisplay(pacesetterIdOpt);
 }
 
-void Scheduler::registerDisplay(PhysicalDisplayId displayId, RefreshRateSelectorPtr selectorPtr) {
+void Scheduler::registerDisplay(PhysicalDisplayId displayId, RefreshRateSelectorPtr selectorPtr,
+                                PhysicalDisplayId activeDisplayId) {
     auto schedulePtr =
             std::make_shared<VsyncSchedule>(selectorPtr->getActiveMode().modePtr, mFeatures,
                                             [this](PhysicalDisplayId id, bool enable) {
                                                 onHardwareVsyncRequest(id, enable);
                                             });
 
-    registerDisplayInternal(displayId, std::move(selectorPtr), std::move(schedulePtr));
+    registerDisplayInternal(displayId, std::move(selectorPtr), std::move(schedulePtr),
+                            activeDisplayId);
 }
 
 void Scheduler::registerDisplayInternal(PhysicalDisplayId displayId,
                                         RefreshRateSelectorPtr selectorPtr,
-                                        VsyncSchedulePtr schedulePtr) {
+                                        VsyncSchedulePtr schedulePtr,
+                                        PhysicalDisplayId activeDisplayId) {
     demotePacesetterDisplay();
 
     auto [pacesetterVsyncSchedule, isNew] = [&]() FTL_FAKE_GUARD(kMainThreadContext) {
@@ -145,7 +148,7 @@
                                                        std::move(schedulePtr), mFeatures)
                                    .second;
 
-        return std::make_pair(promotePacesetterDisplayLocked(), isNew);
+        return std::make_pair(promotePacesetterDisplayLocked(activeDisplayId), isNew);
     }();
 
     applyNewVsyncSchedule(std::move(pacesetterVsyncSchedule));
@@ -158,7 +161,9 @@
     dispatchHotplug(displayId, Hotplug::Connected);
 }
 
-void Scheduler::unregisterDisplay(PhysicalDisplayId displayId) {
+void Scheduler::unregisterDisplay(PhysicalDisplayId displayId, PhysicalDisplayId activeDisplayId) {
+    LOG_ALWAYS_FATAL_IF(displayId == activeDisplayId, "Cannot unregister the active display!");
+
     dispatchHotplug(displayId, Hotplug::Disconnected);
 
     demotePacesetterDisplay();
@@ -173,7 +178,7 @@
         // headless virtual display.)
         LOG_ALWAYS_FATAL_IF(mDisplays.empty(), "Cannot unregister all displays!");
 
-        pacesetterVsyncSchedule = promotePacesetterDisplayLocked();
+        pacesetterVsyncSchedule = promotePacesetterDisplayLocked(activeDisplayId);
     }
     applyNewVsyncSchedule(std::move(pacesetterVsyncSchedule));
 }

services/surfaceflinger/Scheduler/Scheduler.h

diff --git a/services/surfaceflinger/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index ccaa05f..1a4aa79 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -101,9 +101,16 @@
     using ConstVsyncSchedulePtr = std::shared_ptr<const VsyncSchedule>;
     using VsyncSchedulePtr = std::shared_ptr<VsyncSchedule>;
 
-    void registerDisplay(PhysicalDisplayId, RefreshRateSelectorPtr) REQUIRES(kMainThreadContext)
+    // After registration/unregistration, `activeDisplayId` is promoted to pacesetter. Note that the
+    // active display is never unregistered, since hotplug disconnect never happens for activatable
+    // displays, i.e. a foldable's internal displays or otherwise the (internal or external) primary
+    // display.
+    // TODO: b/255635821 - Remove active display parameters.
+    void registerDisplay(PhysicalDisplayId, RefreshRateSelectorPtr,
+                         PhysicalDisplayId activeDisplayId) REQUIRES(kMainThreadContext)
             EXCLUDES(mDisplayLock);
-    void unregisterDisplay(PhysicalDisplayId) REQUIRES(kMainThreadContext) EXCLUDES(mDisplayLock);
+    void unregisterDisplay(PhysicalDisplayId, PhysicalDisplayId activeDisplayId)
+            REQUIRES(kMainThreadContext) EXCLUDES(mDisplayLock);
 
     void run();
 
@@ -390,8 +397,9 @@
     // the caller on the main thread to avoid deadlock, since the timer thread locks it before exit.
     void demotePacesetterDisplay() REQUIRES(kMainThreadContext) EXCLUDES(mDisplayLock, mPolicyLock);
 
-    void registerDisplayInternal(PhysicalDisplayId, RefreshRateSelectorPtr, VsyncSchedulePtr)
-            REQUIRES(kMainThreadContext) EXCLUDES(mDisplayLock);
+    void registerDisplayInternal(PhysicalDisplayId, RefreshRateSelectorPtr, VsyncSchedulePtr,
+                                 PhysicalDisplayId activeDisplayId) REQUIRES(kMainThreadContext)
+            EXCLUDES(mDisplayLock);
 
     struct Policy;