Fix extended range handling when Gamma OETF is used

Populating fakeOutputDataspace got dropped, which turned off the one-off
workaround to bypass skia's color management to encode as gamma 2.2.

Turn it back on to prevent flickers on some devices.

Bug: 293311643
Test: SilkFX test app
Change-Id: I4370756c48fe79c1b4fcbd88a3bf2579fde1bf65
(cherry picked from commit e0bb6f4ff13cc45b61a1b0edccbf875bb3871c89)
diff --git a/libs/renderengine/skia/SkiaRenderEngine.cpp b/libs/renderengine/skia/SkiaRenderEngine.cpp
index 9e9df52..dbb9d28 100644
--- a/libs/renderengine/skia/SkiaRenderEngine.cpp
+++ b/libs/renderengine/skia/SkiaRenderEngine.cpp
@@ -510,7 +510,8 @@
         auto effect =
                 shaders::LinearEffect{.inputDataspace = parameters.layer.sourceDataspace,
                                       .outputDataspace = parameters.outputDataSpace,
-                                      .undoPremultipliedAlpha = parameters.undoPremultipliedAlpha};
+                                      .undoPremultipliedAlpha = parameters.undoPremultipliedAlpha,
+                                      .fakeOutputDataspace = parameters.fakeOutputDataspace};
 
         auto effectIter = mRuntimeEffects.find(effect);
         sk_sp<SkRuntimeEffect> runtimeEffect = nullptr;
@@ -904,12 +905,14 @@
                 (display.outputDataspace & ui::Dataspace::TRANSFER_MASK) ==
                         static_cast<int32_t>(ui::Dataspace::TRANSFER_SRGB);
 
-        const ui::Dataspace runtimeEffectDataspace = !dimInLinearSpace && isExtendedHdr
+        const bool useFakeOutputDataspaceForRuntimeEffect = !dimInLinearSpace && isExtendedHdr;
+
+        const ui::Dataspace fakeDataspace = useFakeOutputDataspaceForRuntimeEffect
                 ? static_cast<ui::Dataspace>(
                           (display.outputDataspace & ui::Dataspace::STANDARD_MASK) |
                           ui::Dataspace::TRANSFER_GAMMA2_2 |
                           (display.outputDataspace & ui::Dataspace::RANGE_MASK))
-                : display.outputDataspace;
+                : ui::Dataspace::UNKNOWN;
 
         // If the input dataspace is range extended, the output dataspace transfer is sRGB
         // and dimmingStage is GAMMA_OETF, dim in linear space instead, and
@@ -1016,7 +1019,8 @@
                                                   .layerDimmingRatio = dimInLinearSpace
                                                           ? layerDimmingRatio
                                                           : 1.f,
-                                                  .outputDataSpace = runtimeEffectDataspace}));
+                                                  .outputDataSpace = display.outputDataspace,
+                                                  .fakeOutputDataspace = fakeDataspace}));
 
             // Turn on dithering when dimming beyond this (arbitrary) threshold...
             static constexpr float kDimmingThreshold = 0.2f;
@@ -1080,7 +1084,8 @@
                                                   .undoPremultipliedAlpha = false,
                                                   .requiresLinearEffect = requiresLinearEffect,
                                                   .layerDimmingRatio = layerDimmingRatio,
-                                                  .outputDataSpace = runtimeEffectDataspace}));
+                                                  .outputDataSpace = display.outputDataspace,
+                                                  .fakeOutputDataspace = fakeDataspace}));
         }
 
         if (layer.disableBlending) {
diff --git a/libs/renderengine/skia/SkiaRenderEngine.h b/libs/renderengine/skia/SkiaRenderEngine.h
index 6457bfa..723e73c 100644
--- a/libs/renderengine/skia/SkiaRenderEngine.h
+++ b/libs/renderengine/skia/SkiaRenderEngine.h
@@ -157,6 +157,7 @@
         bool requiresLinearEffect;
         float layerDimmingRatio;
         const ui::Dataspace outputDataSpace;
+        const ui::Dataspace fakeOutputDataspace;
     };
     sk_sp<SkShader> createRuntimeEffectShader(const RuntimeEffectShaderParameters&);
 
diff --git a/libs/shaders/shaders.cpp b/libs/shaders/shaders.cpp
index c85517a..ef039e5 100644
--- a/libs/shaders/shaders.cpp
+++ b/libs/shaders/shaders.cpp
@@ -168,8 +168,8 @@
 void generateOETF(std::string& shader) {
     // Only support gamma 2.2 for now
     shader.append(R"(
-        float OETF(float3 linear) {
-            return sign(linear) * pow(abs(linear), (1.0 / 2.2));
+        float3 OETF(float3 linear) {
+            return sign(linear) * pow(abs(linear), float3(1.0 / 2.2));
         }
     )");
 }