ozone/drm: support AR30/AB30 framebuffers

Intel Display Controller does not support AR30/AB30 framebuffers,
but only their opaque XR30/XB30 versions. This CL adds a provision
for these formats to |prefer_opaque| when importing a buffer.

This CL was split off crrev.com/c/2072621, and is used for supporting
high bit-depth framebuffers for HDR composition. Tested with that CL
and by playing an HDR video: the primary framebuffer format in
/sys/kernel/debug/dri/0//state correctly changes to XB30, whereas
when there are not HDR quads in the BufferQueue, it's XR24.

Bug: 776093
Change-Id: Iacd0414ea0f0a9dd359796c982ed60d0ee74a737
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2078655
Commit-Queue: Miguel Casas <mcasas@chromium.org>
Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Reviewed-by: Daniele Castagna <dcastagna@chromium.org>
Cr-Commit-Position: refs/heads/master@{#745256}

ui/ozone/platform/drm/gpu/drm_framebuffer.cc

@@ -6,6 +6,7 @@
 
 #include <utility>
 
+#include "ui/gfx/buffer_format_util.h"
 #include "ui/gfx/linux/drm_util_linux.h"
 #include "ui/gfx/linux/gbm_buffer.h"
 #include "ui/ozone/platform/drm/common/drm_util.h"
@@ -28,8 +29,18 @@ scoped_refptr<DrmFramebuffer> DrmFramebuffer::AddFramebuffer(
       modifiers[i] = params.modifier;
   }
 
+  const auto fourcc_format = GetBufferFormatFromFourCCFormat(params.format);
+  const uint32_t opaque_format =
+      GetFourCCFormatForOpaqueFramebuffer(fourcc_format);
+  // Intel Display Controller won't support AR/B30 framebuffers, only XR/B30,
+  // but that doesn't matter because anyway those two bits of alpha are useless;
+  // use the opaque directly in this case.
+  const bool force_opaque = AlphaBitsForBufferFormat(fourcc_format) == 2;
+
+  const auto drm_format = force_opaque ? opaque_format : params.format;
+
   uint32_t framebuffer_id = 0;
-  if (!drm_device->AddFramebuffer2(params.width, params.height, params.format,
+  if (!drm_device->AddFramebuffer2(params.width, params.height, drm_format,
                                    params.handles, params.strides,
                                    params.offsets, modifiers, &framebuffer_id,
                                    params.flags)) {
@@ -37,10 +48,8 @@ scoped_refptr<DrmFramebuffer> DrmFramebuffer::AddFramebuffer(
     return nullptr;
   }
 
-  uint32_t opaque_format = GetFourCCFormatForOpaqueFramebuffer(
-      GetBufferFormatFromFourCCFormat(params.format));
   uint32_t opaque_framebuffer_id = 0;
-  if (opaque_format != params.format &&
+  if (opaque_format != drm_format &&
       !drm_device->AddFramebuffer2(params.width, params.height, opaque_format,
                                    params.handles, params.strides,
                                    params.offsets, modifiers,
@@ -51,9 +60,9 @@ scoped_refptr<DrmFramebuffer> DrmFramebuffer::AddFramebuffer(
   }
 
   return base::MakeRefCounted<DrmFramebuffer>(
-      std::move(drm_device), framebuffer_id, params.format,
-      opaque_framebuffer_id, opaque_format, params.modifier,
-      params.preferred_modifiers, gfx::Size(params.width, params.height));
+      std::move(drm_device), framebuffer_id, drm_format, opaque_framebuffer_id,
+      opaque_format, params.modifier, params.preferred_modifiers,
+      gfx::Size(params.width, params.height));
 }
 
 // static

ui/ozone/platform/drm/gpu/hardware_display_plane_manager_unittest.cc

@@ -18,7 +18,9 @@
 #include "ui/display/types/gamma_ramp_rgb_entry.h"
 #include "ui/gfx/gpu_fence.h"
 #include "ui/gfx/gpu_fence_handle.h"
+#include "ui/gfx/linux/drm_util_linux.h"
 #include "ui/gfx/linux/gbm_buffer.h"
+#include "ui/ozone/platform/drm/common/drm_util.h"
 #include "ui/ozone/platform/drm/gpu/crtc_controller.h"
 #include "ui/ozone/platform/drm/gpu/drm_framebuffer.h"
 #include "ui/ozone/platform/drm/gpu/drm_gpu_util.h"
@@ -937,6 +939,29 @@ TEST_P(HardwareDisplayPlaneManagerTest,
       property_names_, use_atomic_));
 }
 
+// Verifies that formats with 2 bits of alpha decay to opaques for AddFB2().
+TEST_P(HardwareDisplayPlaneManagerTest, ForceOpaqueFormatsForAddFramebuffer) {
+  InitializeDrmState(/*crtc_count=*/3, /*planes_per_crtc=*/1);
+
+  struct {
+    uint32_t input_fourcc;  // FourCC presented to AddFramebuffer.
+    uint32_t used_fourcc;   // FourCC expected to be used in AddFramebuffer.
+  } kFourCCFormats[] = {
+      {DRM_FORMAT_ABGR2101010, DRM_FORMAT_XBGR2101010},
+      // TODO(mcasas): use AR30 when the CLs in crrev.com/c/2068722 have landed.
+      {DRM_FORMAT_XRGB2101010, DRM_FORMAT_XRGB2101010},
+  };
+
+  for (const auto& format_pair : kFourCCFormats) {
+    scoped_refptr<ui::DrmFramebuffer> drm_fb =
+        CreateBufferWithFormat(kDefaultBufferSize, format_pair.input_fourcc);
+
+    EXPECT_EQ(drm_fb->framebuffer_pixel_format(), format_pair.used_fourcc);
+    EXPECT_EQ(drm_fb->opaque_framebuffer_pixel_format(),
+              format_pair.used_fourcc);
+  }
+}
+
 INSTANTIATE_TEST_SUITE_P(All,
                          HardwareDisplayPlaneManagerTest,
                          testing::Values(false, true));

ui/ozone/platform/drm/gpu/mock_gbm_device.cc

@@ -121,6 +121,8 @@ std::unique_ptr<GbmBuffer> MockGbmDevice::CreateBufferWithModifiers(
   switch (format) {
     case DRM_FORMAT_XRGB8888:
     case DRM_FORMAT_ARGB8888:
+    case DRM_FORMAT_XRGB2101010:
+    case DRM_FORMAT_ABGR2101010:
       bytes_per_pixel = 4;
       break;
     case DRM_FORMAT_NV12: