SF: Match followers' refresh rate to pacesetter's
Multi-display refresh rate selection was flawed: The scheduler runs the
refresh rate selection algorithm for each display, and then filters the
candidate modes of each follower to match the pacesetter's refresh rate.
This means that:
1. The followers incorrectly consider refresh rates that don't match the
pacesetter. Because the DM-specified constraint is [59, 61] Hz, some
situations caused selection of a fractional rate (e.g. 59.94) instead
of 60 on certain external displays. The result would be black screens
for several seconds due to mode sets if the selection was not stable.
2. The followers incorrectly evaluate heuristics that should only affect
the pacesetter, e.g. per-surface votes, global signals.
Fix this by teaching RefreshRateSelector about follower displays.
Foldables also benefit from no longer running the algorithm twice.
Fixes: 324188430
Bug: 329111930
Test: No black screen for 4 seconds upon rotating mirrored YouTube.
Test: 60+60 still works on foldables.
Test: RefreshRateSelectorTest.pacesetterConsidered
Change-Id: Ie1b27e81d860a709c85651f068fedb2b496861de
diff --git a/services/surfaceflinger/Scheduler/RefreshRateSelector.cpp b/services/surfaceflinger/Scheduler/RefreshRateSelector.cpp
index 56c29e2..de4fd90 100644
--- a/services/surfaceflinger/Scheduler/RefreshRateSelector.cpp
+++ b/services/surfaceflinger/Scheduler/RefreshRateSelector.cpp
@@ -474,21 +474,23 @@
}
auto RefreshRateSelector::getRankedFrameRates(const std::vector<LayerRequirement>& layers,
- GlobalSignals signals) const -> RankedFrameRates {
+ GlobalSignals signals, Fps pacesetterFps) const
+ -> RankedFrameRates {
+ GetRankedFrameRatesCache cache{layers, signals, pacesetterFps};
+
std::lock_guard lock(mLock);
- if (mGetRankedFrameRatesCache &&
- mGetRankedFrameRatesCache->arguments == std::make_pair(layers, signals)) {
+ if (mGetRankedFrameRatesCache && mGetRankedFrameRatesCache->matches(cache)) {
return mGetRankedFrameRatesCache->result;
}
- const auto result = getRankedFrameRatesLocked(layers, signals);
- mGetRankedFrameRatesCache = GetRankedFrameRatesCache{{layers, signals}, result};
- return result;
+ cache.result = getRankedFrameRatesLocked(layers, signals, pacesetterFps);
+ mGetRankedFrameRatesCache = std::move(cache);
+ return mGetRankedFrameRatesCache->result;
}
auto RefreshRateSelector::getRankedFrameRatesLocked(const std::vector<LayerRequirement>& layers,
- GlobalSignals signals) const
+ GlobalSignals signals, Fps pacesetterFps) const
-> RankedFrameRates {
using namespace fps_approx_ops;
ATRACE_CALL();
@@ -496,6 +498,24 @@
const auto& activeMode = *getActiveModeLocked().modePtr;
+ if (pacesetterFps.isValid()) {
+ ALOGV("Follower display");
+
+ const auto ranking = rankFrameRates(activeMode.getGroup(), RefreshRateOrder::Descending,
+ std::nullopt, [&](FrameRateMode mode) {
+ return mode.modePtr->getPeakFps() == pacesetterFps;
+ });
+
+ if (!ranking.empty()) {
+ ATRACE_FORMAT_INSTANT("%s (Follower display)",
+ to_string(ranking.front().frameRateMode.fps).c_str());
+
+ return {ranking, kNoSignals, pacesetterFps};
+ }
+
+ ALOGW("Follower display cannot follow the pacesetter");
+ }
+
// Keep the display at max frame rate for the duration of powering on the display.
if (signals.powerOnImminent) {
ALOGV("Power On Imminent");