Bug 256802

Summary: [GTK] Extreme screen flickering when using GTK-4 based WebKit build
Product: WebKit Reporter: Douglas R. Reno <renodr>
Component: WebKitGTKAssignee: Nobody <webkit-unassigned>
Status: REOPENED ---    
Severity: Normal CC: bugs-noreply
Priority: P2    
Version: WebKit Nightly Build   
Hardware: PC   
OS: Linux   
Attachments:
Description Flags
Screen Recording of flickering none

Description Douglas R. Reno 2023-05-15 13:11:01 PDT 
Good afternoon,

When using WebKitGTK+-2.40.1 on an Intel Iris GPU (both from a Skylake and a Coffee Lake CPU), applications which use WebKit (MiniBrowser and Epiphany at least) have constant flickers which make the window entirely unusable. It doesn't seem to be reproducible on a 11th-gen Intel CPU, but on a Skylake (6th gen) and a Coffee Lake (8th gen) CPU, it's easily reproducible by opening a window and going to webkit://gpu, webkitgtk.org, or google.com. For what it's worth, Haswell CPUs and their internal GPUs are unaffected, and NVIDIA/AMD GPUs don't seem to be affected either.

There doesn't seem to be any useful console output unfortunately.

Distribution is Linux From Scratch's development version, though it is reproducible on Linux From Scratch 11.3 as well. I'm one of the developers and I'm using a Skylake GPU for testing (HD 530). One of my users who is able to reliably reproduce this uses UHD 630 for a GPU.

This only seems to occur on GTK-4, using a GTK-3 build of MiniBrowser has no problems.

Current versions of applications in use:
 - Kernel 6.2.11
 - Mesa-23.0.2
 - Cairo-1.17.6 (tried 1.17.8 as well, no difference)
 - gstreamer-1.22.2
 - Xorg-Server-21.1.8
 - glibc-2.37
 - gtk-4.10.3

It seems to show up regardless of desktop environment as well.

I've tried downgrading GTK-4 all the way back to 4.8.3 and Mesa to 22.3.5 and it had no difference. Also attempted was downgrading intel-media-driver.

However, using WebKitGTK-2.41.3 shows no problems at all, so I don't think this is a problem with the current development version. I'm not sure how to tell exactly when it was fixed though.

I can downgrade to 2.40.1 and try getting a video if desired.
Comment 1 Douglas R. Reno 2023-05-16 10:24:56 PDT 
Closing since it seems to be fixed somewhere in the stable branch for 2.40.
Comment 2 Douglas R. Reno 2023-06-12 07:07:18 PDT 
Reopening as it's still happening with WebKitGTK-2.40.2.
Comment 3 Douglas R. Reno 2023-06-12 07:07:54 PDT 
Created attachment 466666 [details]
Screen Recording of flickering
Comment 4 Douglas R. Reno 2023-06-12 07:08:12 PDT 
Added a screen recording of the flickering problems
Comment 5 Douglas R. Reno 2023-06-12 07:11:04 PDT 
Some new information:

We're now using GTK-4.10.3, but there is no difference.

Using the unstable version, 2.41.4, fixes the problem. My guess is because it is using DMABUF instead of WPE/X11, because if I pass WEBKIT_DISABLE_DMABUF_RENDERER=1 to MiniBrowser, the problem is still there.

Please let me know if you need any further information. I've got several users now having problems with it