ADL-P: No Screen after login to Desktop on sku with 3840x2400 panel

• -- system architecture: x86_64
• -- kernel version: ubuntu 5.14-oem with adl-p related commits(backport from drmtip)
• -- Linux distribution: Ubuntu
• -- Display connector: eDP

When change the resolution to 3840x2400 in settings, the screen turns black and got the error. we would get this error,

[drm] ERROR CPU pipe A FIFO underrun: soft, transcoder.

After backported the ADL-P related commits from drmtip and still got the issue. dmesg_drm0x1ff_20211022
drm logs with underrun error,dmesg_20211025

here's video. VID_20211022_152144

Please all all possible details as given here: https://gitlab.freedesktop.org/drm/intel/-/wikis/How-to-file-i915-bugs

In the log attached, I can't find that "A FIFO underrun" message. Could you please attach the log with this message, so that we can check, what was happening prior to this.

@stanislav.lisovskiy have uploaded the log with error.

changed the description

changed the description

1. drop require_force_probe, when change resolution to 4k, got the error
   [drm] ERROR CPU pipe A FIFO underrun: soft, transcoder.
   dmesg_drmtip_20211108
2. require_force_probe is enbabled on drm-tip and i915 would not be used and use efifb. If use efifb, the 4k resolution would work well. lsmod_20211104

mentioned in issue #4343 (closed)

The drm-tip: 2021y-12m-03d-11h-43m-38s UTC integration manifest looks good for this issue.

So we can close this now?

@jani.saarinen

Could you help to indicate what commit fix the issue?

Thanks,

Hi, @stanislav.lisovskiy , @vsyrjala do you have any idea on this what could have fixed?

Perhaps commit 4fe7907f3775 ("drm/i915/display/adlp: Disable underrun recovery") ?

@vsyrjala after applied the commit 4fe7907f377, 4k works well. but as per this commit, it disable the underrun recovery and i think the underrun error would not be shown up. After idle 2~3 hours and keep with 4k, i found the underrun error was oberserved agian but 4k works well. is it a expected behavior?

added Community platform: ADL_P labels

assigned to @raviteja

Underruns are still detect even with that "underrun recovery" stuff disabled. It was just supposed to be some fancier way for the hardware to deal with them, but it didn't work out in the end so got nuked.

Underruns shouldn't really happen, if they still do but with less dramatic consequences then I think it's best to file a new bug for that. Closing this one.

closed