Allow GPU composition to occur at a lower resolution

Add a vendor-specified system property to allow GPU fallback composition to occur at a lower resolution than the display mode resolution.

Bug: 144574809

Test: Tested with sysprop disabled, and tested backport in Android Q with sysprop enabled. Unable to test on Android R due to device issues.

Change-Id: I02948ce72f49d20416d0e4dd45a4cffe99e28820
diff --git a/services/surfaceflinger/DisplayHardware/FramebufferSurface.cpp b/services/surfaceflinger/DisplayHardware/FramebufferSurface.cpp
index 36544b6..aeffb0e 100644
--- a/services/surfaceflinger/DisplayHardware/FramebufferSurface.cpp
+++ b/services/surfaceflinger/DisplayHardware/FramebufferSurface.cpp
@@ -57,9 +57,12 @@
  */
 
 FramebufferSurface::FramebufferSurface(HWComposer& hwc, DisplayId displayId,
-                                       const sp<IGraphicBufferConsumer>& consumer)
+                                       const sp<IGraphicBufferConsumer>& consumer,
+                                       uint32_t maxWidth, uint32_t maxHeight)
       : ConsumerBase(consumer),
         mDisplayId(displayId),
+        mMaxWidth(maxWidth),
+        mMaxHeight(maxHeight),
         mCurrentBufferSlot(-1),
         mCurrentBuffer(),
         mCurrentFence(Fence::NO_FENCE),
@@ -75,14 +78,16 @@
                                        GRALLOC_USAGE_HW_RENDER |
                                        GRALLOC_USAGE_HW_COMPOSER);
     const auto& activeConfig = mHwc.getActiveConfig(displayId);
-    mConsumer->setDefaultBufferSize(activeConfig->getWidth(),
-            activeConfig->getHeight());
+    ui::Size limitedSize =
+            limitFramebufferSize(activeConfig->getWidth(), activeConfig->getHeight());
+    mConsumer->setDefaultBufferSize(limitedSize.width, limitedSize.height);
     mConsumer->setMaxAcquiredBufferCount(
             SurfaceFlinger::maxFrameBufferAcquiredBuffers - 1);
 }
 
-void FramebufferSurface::resizeBuffers(const uint32_t width, const uint32_t height) {
-    mConsumer->setDefaultBufferSize(width, height);
+void FramebufferSurface::resizeBuffers(uint32_t width, uint32_t height) {
+    ui::Size limitedSize = limitFramebufferSize(width, height);
+    mConsumer->setDefaultBufferSize(limitedSize.width, limitedSize.height);
 }
 
 status_t FramebufferSurface::beginFrame(bool /*mustRecompose*/) {
@@ -177,6 +182,29 @@
     }
 }
 
+ui::Size FramebufferSurface::limitFramebufferSize(uint32_t width, uint32_t height) {
+    // TODO(b/149495759): Use the ui::Size constructor once it no longer is broken.
+    ui::Size framebufferSize;
+    framebufferSize.width = width;
+    framebufferSize.height = height;
+    bool wasLimited = true;
+    if (width > mMaxWidth && mMaxWidth != 0) {
+        float aspectRatio = float(width) / float(height);
+        framebufferSize.height = mMaxWidth / aspectRatio;
+        framebufferSize.width = mMaxWidth;
+        wasLimited = true;
+    }
+    if (height > mMaxHeight && mMaxHeight != 0) {
+        float aspectRatio = float(width) / float(height);
+        framebufferSize.height = mMaxHeight;
+        framebufferSize.width = mMaxHeight * aspectRatio;
+        wasLimited = true;
+    }
+    ALOGI_IF(wasLimited, "framebuffer size has been limited to [%dx%d] from [%dx%d]",
+             framebufferSize.width, framebufferSize.height, width, height);
+    return framebufferSize;
+}
+
 void FramebufferSurface::dumpAsString(String8& result) const {
     Mutex::Autolock lock(mMutex);
     result.appendFormat("  FramebufferSurface: dataspace: %s(%d)\n",
diff --git a/services/surfaceflinger/DisplayHardware/FramebufferSurface.h b/services/surfaceflinger/DisplayHardware/FramebufferSurface.h
index 7f451a5..a1859f3 100644
--- a/services/surfaceflinger/DisplayHardware/FramebufferSurface.h
+++ b/services/surfaceflinger/DisplayHardware/FramebufferSurface.h
@@ -23,6 +23,7 @@
 #include <compositionengine/DisplaySurface.h>
 #include <compositionengine/impl/HwcBufferCache.h>
 #include <gui/ConsumerBase.h>
+#include <ui/Size.h>
 
 #include "DisplayIdentification.h"
 
@@ -39,7 +40,8 @@
 class FramebufferSurface : public ConsumerBase, public compositionengine::DisplaySurface {
 public:
     FramebufferSurface(HWComposer& hwc, DisplayId displayId,
-                       const sp<IGraphicBufferConsumer>& consumer);
+                       const sp<IGraphicBufferConsumer>& consumer, uint32_t maxWidth,
+                       uint32_t maxHeight);
 
     virtual status_t beginFrame(bool mustRecompose);
     virtual status_t prepareFrame(CompositionType compositionType);
@@ -47,7 +49,7 @@
     virtual void onFrameCommitted();
     virtual void dumpAsString(String8& result) const;
 
-    virtual void resizeBuffers(const uint32_t width, const uint32_t height);
+    virtual void resizeBuffers(uint32_t width, uint32_t height);
 
     virtual const sp<Fence>& getClientTargetAcquireFence() const override;
 
@@ -58,6 +60,9 @@
 
     virtual void dumpLocked(String8& result, const char* prefix) const;
 
+    // Limits the width and height by the maximum width specified in the constructor.
+    ui::Size limitFramebufferSize(uint32_t width, uint32_t height);
+
     // nextBuffer waits for and then latches the next buffer from the
     // BufferQueue and releases the previously latched buffer to the
     // BufferQueue.  The new buffer is returned in the 'buffer' argument.
@@ -66,6 +71,14 @@
 
     const DisplayId mDisplayId;
 
+    // Framebuffer size has a dimension limitation in pixels based on the graphics capabilities of
+    // the device.
+    const uint32_t mMaxWidth;
+
+    // Framebuffer size has a dimension limitation in pixels based on the graphics capabilities of
+    // the device.
+    const uint32_t mMaxHeight;
+
     // mCurrentBufferIndex is the slot index of the current buffer or
     // INVALID_BUFFER_SLOT to indicate that either there is no current buffer
     // or the buffer is not associated with a slot.
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 163a1c7..5a73727 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -217,6 +217,8 @@
 bool SurfaceFlinger::hasSyncFramework;
 bool SurfaceFlinger::useVrFlinger;
 int64_t SurfaceFlinger::maxFrameBufferAcquiredBuffers;
+uint32_t SurfaceFlinger::maxGraphicsWidth;
+uint32_t SurfaceFlinger::maxGraphicsHeight;
 bool SurfaceFlinger::hasWideColorDisplay;
 ui::Rotation SurfaceFlinger::internalDisplayOrientation = ui::ROTATION_0;
 bool SurfaceFlinger::useColorManagement;
@@ -283,6 +285,9 @@
 
     maxFrameBufferAcquiredBuffers = max_frame_buffer_acquired_buffers(2);
 
+    maxGraphicsWidth = std::max(max_graphics_width(0), 0);
+    maxGraphicsHeight = std::max(max_graphics_height(0), 0);
+
     hasWideColorDisplay = has_wide_color_display(false);
 
     useColorManagement = use_color_management(false);
@@ -2593,7 +2598,8 @@
                              state.surface.get());
 
                     LOG_ALWAYS_FATAL_IF(!displayId);
-                    dispSurface = new FramebufferSurface(getHwComposer(), *displayId, bqConsumer);
+                    dispSurface = new FramebufferSurface(getHwComposer(), *displayId, bqConsumer,
+                                                         maxGraphicsWidth, maxGraphicsHeight);
                     producer = bqProducer;
                 }
 
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index e7f9930..7586793 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -42,6 +42,7 @@
 #include <system/graphics.h>
 #include <ui/FenceTime.h>
 #include <ui/PixelFormat.h>
+#include <ui/Size.h>
 #include <utils/Errors.h>
 #include <utils/KeyedVector.h>
 #include <utils/RefBase.h>
@@ -225,6 +226,11 @@
     // FramebufferSurface
     static int64_t maxFrameBufferAcquiredBuffers;
 
+    // Controls the maximum width and height in pixels that the graphics pipeline can support for
+    // GPU fallback composition. For example, 8k devices with 4k GPUs, or 4k devices with 2k GPUs.
+    static uint32_t maxGraphicsWidth;
+    static uint32_t maxGraphicsHeight;
+
     // Indicate if a device has wide color gamut display. This is typically
     // found on devices with wide color gamut (e.g. Display-P3) display.
     static bool hasWideColorDisplay;
diff --git a/services/surfaceflinger/SurfaceFlingerProperties.cpp b/services/surfaceflinger/SurfaceFlingerProperties.cpp
index f3352a5..9d78702 100644
--- a/services/surfaceflinger/SurfaceFlingerProperties.cpp
+++ b/services/surfaceflinger/SurfaceFlingerProperties.cpp
@@ -70,6 +70,22 @@
             defaultValue);
 }
 
+int32_t max_graphics_width(int32_t defaultValue) {
+    auto temp = SurfaceFlingerProperties::max_graphics_width();
+    if (temp.has_value()) {
+        return *temp;
+    }
+    return defaultValue;
+}
+
+int32_t max_graphics_height(int32_t defaultValue) {
+    auto temp = SurfaceFlingerProperties::max_graphics_height();
+    if (temp.has_value()) {
+        return *temp;
+    }
+    return defaultValue;
+}
+
 bool has_wide_color_display(bool defaultValue) {
     auto temp = SurfaceFlingerProperties::has_wide_color_display();
     if (temp.has_value()) {
diff --git a/services/surfaceflinger/SurfaceFlingerProperties.h b/services/surfaceflinger/SurfaceFlingerProperties.h
index 12c711a..c63adfe 100644
--- a/services/surfaceflinger/SurfaceFlingerProperties.h
+++ b/services/surfaceflinger/SurfaceFlingerProperties.h
@@ -37,6 +37,9 @@
 
 int64_t max_frame_buffer_acquired_buffers(int64_t defaultValue);
 
+int32_t max_graphics_width(int32_t defaultValue);
+int32_t max_graphics_height(int32_t defaultValue);
+
 bool has_wide_color_display(bool defaultValue);
 
 bool running_without_sync_framework(bool defaultValue);
diff --git a/services/surfaceflinger/sysprop/SurfaceFlingerProperties.sysprop b/services/surfaceflinger/sysprop/SurfaceFlingerProperties.sysprop
index 155f718..cfc301b 100644
--- a/services/surfaceflinger/sysprop/SurfaceFlingerProperties.sysprop
+++ b/services/surfaceflinger/sysprop/SurfaceFlingerProperties.sysprop
@@ -67,6 +67,26 @@
     prop_name: "ro.surface_flinger.max_frame_buffer_acquired_buffers"
 }
 
+# Controls the maximum width in pixels that the graphics pipeline can support for GPU fallback
+# composition. For example, 8k displays with 4k GPUs, or 4k displays with 2k GPUs.
+prop {
+    api_name: "max_graphics_width"
+    type: Integer
+    scope: System
+    access: Readonly
+    prop_name: "ro.surface_flinger.max_graphics_width"
+}
+
+# Controls the maximum height in pixels that the graphics pipeline can support for GPU fallback
+# composition. For example, 8k displays with 4k GPUs, or 4k displays with 2k GPUs.
+prop {
+    api_name: "max_graphics_height"
+    type: Integer
+    scope: System
+    access: Readonly
+    prop_name: "ro.surface_flinger.max_graphics_height"
+}
+
 # hasWideColorDisplay indicates that the device has
 # or can support a wide-color display, e.g. color space
 # greater than sRGB. Typical display may have same
diff --git a/services/surfaceflinger/sysprop/api/SurfaceFlingerProperties-current.txt b/services/surfaceflinger/sysprop/api/SurfaceFlingerProperties-current.txt
index e62c127..ba60a7d 100644
--- a/services/surfaceflinger/sysprop/api/SurfaceFlingerProperties-current.txt
+++ b/services/surfaceflinger/sysprop/api/SurfaceFlingerProperties-current.txt
@@ -62,6 +62,16 @@
     prop_name: "ro.surface_flinger.max_frame_buffer_acquired_buffers"
   }
   prop {
+    api_name: "max_graphics_height"
+    type: Integer
+    prop_name: "ro.surface_flinger.max_graphics_height"
+  }
+  prop {
+    api_name: "max_graphics_width"
+    type: Integer
+    prop_name: "ro.surface_flinger.max_graphics_width"
+  }
+  prop {
     api_name: "max_virtual_display_dimension"
     type: Long
     prop_name: "ro.surface_flinger.max_virtual_display_dimension"