Fwd: Thinkpad X13 AMD: Problems with external monitor wake up after suspend

[Thorsten Leemhuis]

[CCing stable list and Mario, who submitted this to 6.1.y]

On 01.12.23 01:30, Bagas Sanjaya wrote:
> 
> I notice a regression report on Bugzilla [1]. Quoting from it:
> 
>> Since kernel version 6.1.57 I have problems with external monitor
>> wakeup after suspend on Thinkpad X13 AMD Gen2 Notebook.
>> 
>> Notebook is in docking station with closed lid. Suspend & Resume.
>> The external monitor gets no signal. After randomly typing
>> Ctrl+Alt+Fn for switchung consoles, the monitor at some point gets
>> signal and is usable again.
>> 
>> It worked with kernel 6.1.56.
>> 
>> I managed to compile a 6.1.57 kernel and also a 6.1.64 kernel by
>> reverting the changes from commit ec5fa9 "drm/amd/display: Adjust
>> the MST resume flow"
>> (https://github.com/torvalds/linux/commit/ec5fa9fcdeca69edf7dab5ca3b2e0ceb1c08fe9a?diff=split&w=1?diff=split&w=1)
>> and with this suspend & resume worked like before without any
>> problems.
> [...]
> [1]: https://bugzilla.kernel.org/show_bug.cgi?id=218211

We have a small problem here: that error might happen because
ec5fa9fcdeca69 ("drm/amd/display: Adjust the MST resume flow")
[v6.6-rc2] contains a bug or because something it needs was not
backported to 6.1.y.

Maybe one of the developers among the recipients has a idea. Oliver, but
if none of them replies any time soon, it would be best if you'd check
if 6.6 (and/or 6.7-rc) is affected as well; and if reverting it there
fixes it, too.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
https://linux-regtracking.leemhuis.info/about/#tldr
If I did something stupid, please tell me, as explained on that page.