1686976 - The browser window flickers with artifacts when resized with WebRender on Ubuntu 20.04

Status: RESOLVED DUPLICATE of bug 1547974

(Core :: Graphics: WebRender, defect)

Description

[Simona Badau, Desktop QA]

Attachment: aboutSupport

Affected platform
Ubuntu 20.04 x64

Affected versions
Firefox 84.0.2
Firefox 85 beta 9
Nightly 86.0a1

Steps to reproduce

1. Launch Firefox with a new profile
2. Open a new tab
3. From the bottom try to resize the window up and down.

Expected result
The browser should be properly resized, without flickering or artifacts.

Actual Result
The browser's window flickers and artifacts can be seen. Please see the video for more details https://imgur.com/z1nvxkf

If I disable WebRender (by setting the preference gfx.webrender.force-disabled to true) then the issue is no longer reproducible.

Comment 1

[Jim Mathies [:jimm]]

Window Protocol: x11
Desktop Environment: gnome
Off Main Thread Painting Enabled: true
Off Main Thread Painting Worker Count: 3
Target Frame Rate: 60
GPU #1
Active: Yes
Description: Mesa Intel(R) HD Graphics 530 (SKL GT2)
Vendor ID: 0x8086
Device ID: 0x1912
Driver Vendor: mesa/iris
Driver Version: 20.0.8.0

Comment 2

[Jeff Muizelaar [:jrmuizel]]

Simona, can you try with gfx.webrender.force-disabled=true and layers.acceleration.force-enabled=true

Comment 3

[Simona Badau, Desktop QA]

(In reply to Jeff Muizelaar [:jrmuizel] from comment #2)

Simona, can you try with gfx.webrender.force-disabled=true and layers.acceleration.force-enabled=true

When I set both settings to true, the issue is reproducible.

Comment 4

[Robert Mader [:rmader]]

Apparently a duplicate of bug 1547974