Set LOW category to 48 fps

Based on UX.

Bug: 343775394
Test: libsurfaceflinger_unittest
Flag: EXEMPT bugfix
Change-Id: I493152d82e96b3a1a7397fcf6a19077392cf4c23
diff --git a/services/surfaceflinger/Scheduler/RefreshRateSelector.cpp b/services/surfaceflinger/Scheduler/RefreshRateSelector.cpp
index 2c66492..76fbef0 100644
--- a/services/surfaceflinger/Scheduler/RefreshRateSelector.cpp
+++ b/services/surfaceflinger/Scheduler/RefreshRateSelector.cpp
@@ -1636,7 +1636,7 @@
         case FrameRateCategory::Normal:
             return FpsRange{60_Hz, 120_Hz};
         case FrameRateCategory::Low:
-            return FpsRange{30_Hz, 120_Hz};
+            return FpsRange{48_Hz, 120_Hz};
         case FrameRateCategory::HighHint:
         case FrameRateCategory::NoPreference:
         case FrameRateCategory::Default:
diff --git a/services/surfaceflinger/tests/unittests/RefreshRateSelectorTest.cpp b/services/surfaceflinger/tests/unittests/RefreshRateSelectorTest.cpp
index cf9a7d3..06c4e30 100644
--- a/services/surfaceflinger/tests/unittests/RefreshRateSelectorTest.cpp
+++ b/services/surfaceflinger/tests/unittests/RefreshRateSelectorTest.cpp
@@ -1562,7 +1562,7 @@
             // When frame rates get an equal score, the lower is chosen, unless there are Max votes.
             {0_Hz, FrameRateCategory::High, 90_Hz},
             {0_Hz, FrameRateCategory::Normal, 60_Hz},
-            {0_Hz, FrameRateCategory::Low, 30_Hz},
+            {0_Hz, FrameRateCategory::Low, 60_Hz},
             {0_Hz, FrameRateCategory::NoPreference, 60_Hz},
 
             // Cases that have both desired frame rate and frame rate category requirements.
@@ -1609,6 +1609,77 @@
     }
 }
 
+TEST_P(RefreshRateSelectorTest, getBestFrameRateMode_withFrameRateCategory_120_vrr) {
+    if (GetParam() != Config::FrameRateOverride::Enabled) {
+        return;
+    }
+
+    SET_FLAG_FOR_TEST(flags::vrr_config, true);
+    // Device with VRR config mode
+    auto selector = createSelector(kVrrMode_120, kModeId120);
+
+    struct Case {
+        // Params
+        Fps desiredFrameRate = 0_Hz;
+        FrameRateCategory frameRateCategory = FrameRateCategory::Default;
+
+        // Expected result
+        Fps expectedFrameRate = 0_Hz;
+    };
+
+    // Prepare a table with the vote and the expected refresh rate
+    const std::initializer_list<Case> testCases = {
+            // Cases that only have frame rate category requirements, but no desired frame rate.
+            // When frame rates get an equal score, the lower is chosen, unless there are Max votes.
+            {0_Hz, FrameRateCategory::High, 120_Hz},
+            {0_Hz, FrameRateCategory::Normal, 60_Hz},
+            {0_Hz, FrameRateCategory::Low, 48_Hz},
+            {0_Hz, FrameRateCategory::NoPreference, 120_Hz},
+
+            // Cases that have both desired frame rate and frame rate category requirements.
+            {24_Hz, FrameRateCategory::High, 120_Hz},
+            {30_Hz, FrameRateCategory::High, 120_Hz},
+            {12_Hz, FrameRateCategory::Normal, 60_Hz},
+            {24_Hz, FrameRateCategory::Low, 48_Hz},
+            {30_Hz, FrameRateCategory::NoPreference, 30_Hz},
+
+            // Cases that only have desired frame rate.
+            {30_Hz, FrameRateCategory::Default, 30_Hz},
+    };
+
+    for (auto testCase : testCases) {
+        std::vector<LayerRequirement> layers;
+        ALOGI("**** %s: Testing desiredFrameRate=%s, frameRateCategory=%s", __func__,
+              to_string(testCase.desiredFrameRate).c_str(),
+              ftl::enum_string(testCase.frameRateCategory).c_str());
+
+        if (testCase.desiredFrameRate.isValid()) {
+            std::stringstream ss;
+            ss << to_string(testCase.desiredFrameRate) << "ExplicitDefault";
+            LayerRequirement layer = {.name = ss.str(),
+                                      .vote = LayerVoteType::ExplicitDefault,
+                                      .desiredRefreshRate = testCase.desiredFrameRate,
+                                      .weight = 1.f};
+            layers.push_back(layer);
+        }
+
+        if (testCase.frameRateCategory != FrameRateCategory::Default) {
+            std::stringstream ss;
+            ss << "ExplicitCategory (" << ftl::enum_string(testCase.frameRateCategory) << ")";
+            LayerRequirement layer = {.name = ss.str(),
+                                      .vote = LayerVoteType::ExplicitCategory,
+                                      .frameRateCategory = testCase.frameRateCategory,
+                                      .weight = 1.f};
+            layers.push_back(layer);
+        }
+
+        EXPECT_EQ(testCase.expectedFrameRate, selector.getBestFrameRateMode(layers).fps)
+                << "Did not get expected frame rate for frameRate="
+                << to_string(testCase.desiredFrameRate)
+                << " category=" << ftl::enum_string(testCase.frameRateCategory);
+    }
+}
+
 TEST_P(RefreshRateSelectorTest,
        getBestFrameRateMode_withFrameRateCategoryMultiLayers_30_60_90_120) {
     auto selector = createSelector(makeModes(kMode30, kMode60, kMode90, kMode120), kModeId60);
@@ -2140,14 +2211,14 @@
             // These layers may switch modes because smoothSwitchOnly=false.
             {FrameRateCategory::Default, false, 120_Hz, kModeId120},
             {FrameRateCategory::NoPreference, false, 120_Hz, kModeId120},
-            {FrameRateCategory::Low, false, 30_Hz, kModeId60},
+            {FrameRateCategory::Low, false, 60_Hz, kModeId60},
             {FrameRateCategory::Normal, false, 60_Hz, kModeId60},
             {FrameRateCategory::High, false, 120_Hz, kModeId120},
 
             // These layers cannot change mode due to smoothSwitchOnly, and will definitely use
             // active mode (120Hz).
             {FrameRateCategory::NoPreference, true, 120_Hz, kModeId120},
-            {FrameRateCategory::Low, true, 40_Hz, kModeId120},
+            {FrameRateCategory::Low, true, 120_Hz, kModeId120},
             {FrameRateCategory::Normal, true, 120_Hz, kModeId120},
             {FrameRateCategory::High, true, 120_Hz, kModeId120},
     };
@@ -2207,13 +2278,13 @@
             {FrameRateCategory::Default, false, 120_Hz},
             // TODO(b/266481656): Once this bug is fixed, NoPreference should be a lower frame rate.
             {FrameRateCategory::NoPreference, false, 120_Hz},
-            {FrameRateCategory::Low, false, 30_Hz},
+            {FrameRateCategory::Low, false, 48_Hz},
             {FrameRateCategory::Normal, false, 60_Hz},
             {FrameRateCategory::High, false, 120_Hz},
             {FrameRateCategory::Default, true, 120_Hz},
             // TODO(b/266481656): Once this bug is fixed, NoPreference should be a lower frame rate.
             {FrameRateCategory::NoPreference, true, 120_Hz},
-            {FrameRateCategory::Low, true, 30_Hz},
+            {FrameRateCategory::Low, true, 48_Hz},
             {FrameRateCategory::Normal, true, 60_Hz},
             {FrameRateCategory::High, true, 120_Hz},
     };