commit 92900f8188bf923308c0b081c0a44c0f6ae36724
author Dominik Laskowski <domlaskowski@google.com> Tue Jun 25 11:50:43 2024 -0400
committer Dominik Laskowski <domlaskowski@google.com> Mon Jul 01 18:17:22 2024 -0400
tree c911c2c92bbb0672ee6e5f92f440fdfadc3cf74e
parent 6429b0b304e3684ae94366fb07c00c8b099c3138

SF: Generalize immediate mode set to multi-display

When initiating a mode set, HWC may request an immediate mode change, in
which case SF finalizes the change on the same (rather than next) frame.
However, this would only be honored for at most one display, and further
requests would be dropped.

This was a historical hack: The loop used to iterate over mDisplays, and
finalizeDisplayModeChange may recreate/invalidate the DisplayDevice. Now
that the loop is over the immutable mPhysicalDisplays, the DisplayDevice
can be safely recreated within the loop.

Note that the only known user of this code path is ATV, so multi-display
devices should not be affected by this change.

Bug: 255635711
Flag: EXEMPT refactor
Test: DisplayModeSwitchingTest (WithoutRefreshRequired cases)
Change-Id: I842e39c2c5509de99b80fa9561ecb13b66f98c40

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 5b40acf..bba27b2 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1481,8 +1481,6 @@
 void SurfaceFlinger::initiateDisplayModeChanges() {
     ATRACE_CALL();
 
-    std::optional<PhysicalDisplayId> displayToUpdateImmediately;
-
     for (const auto& [displayId, physical] : FTL_FAKE_GUARD(mStateLock, mPhysicalDisplays)) {
         auto desiredModeOpt = mDisplayModeController.getDesiredMode(displayId);
         if (!desiredModeOpt) {
@@ -1536,21 +1534,14 @@
         if (outTimeline.refreshRequired) {
             scheduleComposite(FrameHint::kNone);
         } else {
-            // TODO(b/255635711): Remove `displayToUpdateImmediately` to `finalizeDisplayModeChange`
-            // for all displays. This was only needed when the loop iterated over `mDisplays` rather
-            // than `mPhysicalDisplays`.
-            displayToUpdateImmediately = displayId;
-        }
-    }
+            // HWC has requested to apply the mode change immediately rather than on the next frame.
+            finalizeDisplayModeChange(displayId);
 
-    if (displayToUpdateImmediately) {
-        const auto displayId = *displayToUpdateImmediately;
-        finalizeDisplayModeChange(displayId);
-
-        const auto desiredModeOpt = mDisplayModeController.getDesiredMode(displayId);
-        if (desiredModeOpt &&
-            mDisplayModeController.getActiveMode(displayId) == desiredModeOpt->mode) {
-            applyActiveMode(displayId);
+            const auto desiredModeOpt = mDisplayModeController.getDesiredMode(displayId);
+            if (desiredModeOpt &&
+                mDisplayModeController.getActiveMode(displayId) == desiredModeOpt->mode) {
+                applyActiveMode(displayId);
+            }
         }
     }
 }