[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/ec5fa9fcdeca69edf7dab5ca3b2e0ceb1c0...) 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.