commit dc0b3a7e62eceeb4026cfa233b423296bbab5b7f
author Ady Abraham <adyabr@google.com> Wed Jan 04 16:58:27 2023 -0800
committer Ady Abraham <adyabr@google.com> Wed Jan 04 16:58:45 2023 -0800
tree af81336bae042c1fdd7dc8151e86d490486d824d
parent 1d17304315483ff0267435ff0ebd6d417ae630f8

SF: Fix refresh rate selection for low physical refresh rates

With the render frame rate introduction of physical refresh rate
divisors, a hardcoded minimum frame rate was added. This minimum was
incorrectly applied to physical refresh rates in addition to divisors,
which prevented lower physical refresh rates to be enumarated.

Test: atest libsurfaceflinger_unittest
Bug: 261520501
Change-Id: I597f9c61bd7a0e8fd2dc16415e36d97c1417f74f

services/surfaceflinger/Scheduler/RefreshRateSelector.cpp

diff --git a/services/surfaceflinger/Scheduler/RefreshRateSelector.cpp b/services/surfaceflinger/Scheduler/RefreshRateSelector.cpp
index a05d3df..21f5c68 100644
--- a/services/surfaceflinger/Scheduler/RefreshRateSelector.cpp
+++ b/services/surfaceflinger/Scheduler/RefreshRateSelector.cpp
@@ -180,7 +180,7 @@
         for (auto divisor = start; divisor <= end; divisor++) {
             const auto fps = mode->getFps() / divisor;
             using fps_approx_ops::operator<;
-            if (fps < kMinSupportedFrameRate) {
+            if (divisor > 1 && fps < kMinSupportedFrameRate) {
                 break;
             }
 

services/surfaceflinger/tests/unittests/RefreshRateSelectorTest.cpp

diff --git a/services/surfaceflinger/tests/unittests/RefreshRateSelectorTest.cpp b/services/surfaceflinger/tests/unittests/RefreshRateSelectorTest.cpp
index a3b3c4c..06f45f9 100644
--- a/services/surfaceflinger/tests/unittests/RefreshRateSelectorTest.cpp
+++ b/services/surfaceflinger/tests/unittests/RefreshRateSelectorTest.cpp
@@ -153,6 +153,9 @@
     static constexpr DisplayModeId kModeId30Frac{9};
     static constexpr DisplayModeId kModeId60Frac{10};
     static constexpr DisplayModeId kModeId35{11};
+    static constexpr DisplayModeId kModeId1{12};
+    static constexpr DisplayModeId kModeId5{13};
+    static constexpr DisplayModeId kModeId10{14};
 
     static inline const ftl::NonNull<DisplayModePtr> kMode60 =
             ftl::as_non_null(createDisplayMode(kModeId60, 60_Hz));
@@ -190,6 +193,12 @@
             ftl::as_non_null(createDisplayMode(kModeId24, 24_Hz));
     static inline const ftl::NonNull<DisplayModePtr> kMode24Frac =
             ftl::as_non_null(createDisplayMode(kModeId24Frac, 23.976_Hz));
+    static inline const ftl::NonNull<DisplayModePtr> kMode1 =
+            ftl::as_non_null(createDisplayMode(kModeId1, 1_Hz));
+    static inline const ftl::NonNull<DisplayModePtr> kMode5 =
+            ftl::as_non_null(createDisplayMode(kModeId5, 5_Hz));
+    static inline const ftl::NonNull<DisplayModePtr> kMode10 =
+            ftl::as_non_null(createDisplayMode(kModeId10, 10_Hz));
 
     // Test configurations.
     static inline const DisplayModes kModes_60 = makeModes(kMode60);
@@ -212,6 +221,7 @@
     static inline const DisplayModes kModes_25_30_50_60 =
             makeModes(kMode60, kMode90, kMode72_G1, kMode120_G1, kMode30_G1, kMode25_G1, kMode50);
     static inline const DisplayModes kModes_60_120 = makeModes(kMode60, kMode120);
+    static inline const DisplayModes kModes_1_5_10 = makeModes(kMode1, kMode5, kMode10);
 
     // This is a typical TV configuration.
     static inline const DisplayModes kModes_24_25_30_50_60_Frac =
@@ -2956,5 +2966,12 @@
     EXPECT_EQ(kMode60, selector.getMinRefreshRateByPolicy());
 }
 
+TEST_P(RefreshRateSelectorTest, SupportsLowPhysicalRefreshRates) {
+    auto selector = createSelector(kModes_1_5_10, kModeId10);
+
+    EXPECT_EQ(kMode10, selector.getMaxRefreshRateByPolicy());
+    EXPECT_EQ(kMode1, selector.getMinRefreshRateByPolicy());
+}
+
 } // namespace
 } // namespace android::scheduler