Flickering occurs since flutter-elinux 3.7.6

[makotosato-at]

Hello.

I am using an i.MX8MP board and weston.
Using flutter-elinux 3.7.6 and #333, I get flickering in my application.
(It works fine in version 3.3.10.)

I attached a video:

flickering.mp4

Window size is 1920x1080.
In the application, movie@30fps(color bars) and scrolling text are displayed.
Is there any solution?

It doesn't solve anything, but I tried the following and it worked fine:

--- a/src/flutter/shell/platform/linux_embedded/surface/elinux_egl_surface.cc
+++ b/src/flutter/shell/platform/linux_embedded/surface/elinux_egl_surface.cc
@@ -189,6 +189,7 @@ void ELinuxEGLSurface::PopulateExistingDamage(const intptr_t fbo_id,
       }
     }
   }
+  existing_damage->damage[0] = {0, 0, 1920, 1080};
 }
 
 // Auxiliary function used to transform a FlutterRect into the format that is

[HidenoriMatsubayashi]

Can you share the test source files you used?

[makotosato-at]

Thanks for your reply.

I attached a test source.
flickering.zip

[0xkelvin]

thanks for raising this, we facing same issues, so would like to follow up

[HidenoriMatsubayashi]

Is this issue reproducible on Linux desktop PC? Does it happen on only i.mx8m + weston?

[makotosato-at]

For now, only imx8mp + weston.

[HidenoriMatsubayashi]

unfortunately, I cannot reproduce this because I don't have imx8mp board.

Can you please try compiler options below?

• Disable USE_DIRTY_REGION_MANAGEMENT
  • See: https://github.com/sony/flutter-embedded-linux/blob/master/CMakeLists.txt#L14
• Enable ENABLE_VSYNC
  • See: https://github.com/sony/flutter-embedded-linux/blob/master/CMakeLists.txt#L17

[makotosato-at]

Thank you.
I tried it, but it did not work.

[HidenoriMatsubayashi]

(It works fine in version 3.3.10.)

Hmm, version 3.7.0 also doesn't work, right? If so, it might depend on flutter/engine.

[HidenoriMatsubayashi]

I found similar issue flutter/flutter#100522

[makotosato-at]

Thanks for the information.
I will watch this issue.

[calvinchengx]

This link to 100522 is impeller related.

Root cause of flickering bug is described here - flutter/flutter#121740

And this line of code is the problem - https://github.com/flutter/engine/blob/4a90fbcd69011f8dd593840a0e901d2cede5398b/flow/layers/display_list_raster_cache_item.cc#L112

There was an attempt to fix this bug here - flutter/engine#39690 - but it created the above chicken-and-egg issue 121740.

The root cause is that picture layers used to declare themselves as able to inherit opacity when they became eligible to cache. The problem is that "eligible to cache" doesn't mean that they will be successful. In particular, we only allow 3 pictures to cache per frame so if there were more than 3 children than all of them might say they can inherit opacity, but only 3 would be telling the truth. The fix requires the children to wait until they successfully cache themselves before they declare that they can inherit opacity. The problem is that if the parent is caching the children then it will tell the children not to cache themselves. This policy prevents double-caching where the parent is caching the children who are also caching themselves. Unfortunately, since the children can never cache themselves, they also never declare that they can inherit opacity. Thus, a chicken and egg situation.

The fix will require some careful decisions about the eligibility and potential eligibility of the children to cache themselves and thus inherit opacity.

[barribarrier]

Same problem.
My app flickers for a few seconds on launch and then stabilizes itself (no more flicker)

x64 linux
Sway: 1.7-1
Flutter-elinux: 3.10.1

[JakeSays]

I'm seeing this same thing, flutter version 3.10.05 and using the X11, wayland, and gbm embedders on both a raspberry pi 3a+, and a radxa zero.