From 4385a96ee16374ebbaf75b0aae756913f25fde4c Mon Sep 17 00:00:00 2001
From: Jonah Williams <jonahwilliams@google.com>
Date: Wed, 28 Aug 2024 18:23:31 -0700
Subject: [PATCH] [Impeller] Use multiple command buffers for blur submission.
 (flutter/engine#54846)

Fixes https://github.com/flutter/flutter/issues/154046

Use three different command buffers when it would be   possible to combine the operations into a single buffer. From testing and user bug reports (see https://github.com/flutter/flutter/issues/154046 ), this sometimes causes deviceLost errors on older Adreno devices. Breaking  the work up into three different command buffers seems to prevent this crash.

I suspect this is due to some internal timeouts we may be hitting in the adreno driver.
---
 .../filters/gaussian_blur_filter_contents.cc  | 31 +++++++++++++++----
 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/engine/src/flutter/impeller/entity/contents/filters/gaussian_blur_filter_contents.cc b/engine/src/flutter/impeller/entity/contents/filters/gaussian_blur_filter_contents.cc
index cf39b60e33..c8fda3376c 100644
--- a/engine/src/flutter/impeller/entity/contents/filters/gaussian_blur_filter_contents.cc
+++ b/engine/src/flutter/impeller/entity/contents/filters/gaussian_blur_filter_contents.cc
@@ -727,9 +727,15 @@ std::optional<Entity> GaussianBlurFilterContents::RenderFilter(
     return result;
   }
 
-  std::shared_ptr<CommandBuffer> command_buffer =
+  // Note: The code below uses three different command buffers when it would be
+  // possible to combine the operations into a single buffer. From testing and
+  // user bug reports (see https://github.com/flutter/flutter/issues/154046 ),
+  // this sometimes causes deviceLost errors on older Adreno devices. Breaking
+  // the work up into three different command buffers seems to prevent this
+  // crash.
+  std::shared_ptr<CommandBuffer> command_buffer_1 =
       renderer.GetContext()->CreateCommandBuffer();
-  if (!command_buffer) {
+  if (!command_buffer_1) {
     return std::nullopt;
   }
 
@@ -738,7 +744,7 @@ std::optional<Entity> GaussianBlurFilterContents::RenderFilter(
       source_expanded_coverage_hint, inputs[0], snapshot_entity);
 
   fml::StatusOr<RenderTarget> pass1_out = MakeDownsampleSubpass(
-      renderer, command_buffer, input_snapshot->texture,
+      renderer, command_buffer_1, input_snapshot->texture,
       input_snapshot->sampler_descriptor, downsample_pass_args, tile_mode_);
 
   if (!pass1_out.ok()) {
@@ -750,8 +756,14 @@ std::optional<Entity> GaussianBlurFilterContents::RenderFilter(
 
   Quad blur_uvs = {Point(0, 0), Point(1, 0), Point(0, 1), Point(1, 1)};
 
+  std::shared_ptr<CommandBuffer> command_buffer_2 =
+      renderer.GetContext()->CreateCommandBuffer();
+  if (!command_buffer_2) {
+    return std::nullopt;
+  }
+
   fml::StatusOr<RenderTarget> pass2_out = MakeBlurSubpass(
-      renderer, command_buffer, /*input_pass=*/pass1_out.value(),
+      renderer, command_buffer_2, /*input_pass=*/pass1_out.value(),
       input_snapshot->sampler_descriptor, tile_mode_,
       BlurParameters{
           .blur_uv_offset = Point(0.0, pass1_pixel_size.y),
@@ -767,6 +779,12 @@ std::optional<Entity> GaussianBlurFilterContents::RenderFilter(
     return std::nullopt;
   }
 
+  std::shared_ptr<CommandBuffer> command_buffer_3 =
+      renderer.GetContext()->CreateCommandBuffer();
+  if (!command_buffer_3) {
+    return std::nullopt;
+  }
+
   // Only ping pong if the first pass actually created a render target.
   auto pass3_destination = pass2_out.value().GetRenderTargetTexture() !=
                                    pass1_out.value().GetRenderTargetTexture()
@@ -774,7 +792,7 @@ std::optional<Entity> GaussianBlurFilterContents::RenderFilter(
                                : std::optional<RenderTarget>(std::nullopt);
 
   fml::StatusOr<RenderTarget> pass3_out = MakeBlurSubpass(
-      renderer, command_buffer, /*input_pass=*/pass2_out.value(),
+      renderer, command_buffer_3, /*input_pass=*/pass2_out.value(),
       input_snapshot->sampler_descriptor, tile_mode_,
       BlurParameters{
           .blur_uv_offset = Point(pass1_pixel_size.x, 0.0),
@@ -792,7 +810,8 @@ std::optional<Entity> GaussianBlurFilterContents::RenderFilter(
 
   if (!renderer.GetContext()
            ->GetCommandQueue()
-           ->Submit(/*buffers=*/{command_buffer})
+           ->Submit(/*buffers=*/{command_buffer_1, command_buffer_2,
+                                 command_buffer_3})
            .ok()) {
     return std::nullopt;
   }