https://bugzilla.kernel.org/show_bug.cgi?id=214991

Bug ID: 214991 Summary: VC4 DRM waiting for flip down makes UI freeze a while with kernel 5.15 Product: Drivers Version: 2.5 Kernel Version: 5.15 Hardware: ARM OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Video(DRI - non Intel) Assignee: drivers_video-dri@kernel-bugs.osdl.org Reporter: jhp@endlessos.org Regression: No

Created attachment 299547 --> https://bugzilla.kernel.org/attachment.cgi?id=299547&action=edit Full dmesg log

I tested Linux mainline kernel 5.15 (aarch64) with enabled VC4 on RPi 4B. I notice UI freezes a while (about 10 seconds) some times.

The kernel shows the error message during the time:

[drm:drm_crtc_commit_wait] *ERROR* flip_done timed out [drm:drm_atomic_helper_wait_for_flip_done] *ERROR* [CRTC:68:crtc-3] flip_done timed out [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CRTC:68:crtc-3] commit wait timed out [drm:drm_crtc_commit_wait] *ERROR* flip_done timed out vc4-drm gpu: [drm] *ERROR* Timed out waiting for commit

It is easy to reproduce this issue by invoking GL related things, for example es2gears.

After detail test, I found it is related to these commits:

f3c420fe19f8 ("drm/vc4: kms: Convert to atomic helpers") 82faa3276012 ("drm/vc4: kms: Remove async modeset semaphore")

This issue cannot be reproduced after I revert the commits.