On my Dell XPS 9560, and Linus post-5.3 git tree, my Dell U3415W is no longer driven from X. The screen goes into standby, and attempting to use it shows: $ xrandr --output DP-1-2-8 --above eDP-1 --auto xrandr: cannot find crtc for output DP-1-2-8 Note that the screen lights up during boot, as it always did. Once lightdm is started, the screen turns off. When I shut the machine down and X terminates, the screen lights back up. I will be adding attachments shortly.
Created attachment 145467 [details] dmesg dmesg output with DRM debug, covering boot and X turn-up
Created attachment 145468 [details] Xorg.0.log Xorg log with the "modeset" driver
Created attachment 145469 [details] [review] git.diff I currently set enable_guc to 2, as I find the graphics behave better with this firmware loaded. I find behaviour is the same with enable_guc set to 0 or 2, and can test in either scenario for you.
The bad commit for me is: commit 574cc4539762561d96b456dbc0544d8898bd4c6e Merge: 3c2edc36a774 945b584c94f8 Author: Linus Torvalds <torvalds@linux-foundation.org> Date: Thu Sep 19 16:24:24 2019 -0700 Merge tag 'drm-next-2019-09-18' of git://anongit.freedesktop.org/drm/drm
(In reply to Tony Vroon from comment #4) > The bad commit for me is: > commit 574cc4539762561d96b456dbc0544d8898bd4c6e > Merge: 3c2edc36a774 945b584c94f8 > Author: Linus Torvalds <torvalds@linux-foundation.org> > Date: Thu Sep 19 16:24:24 2019 -0700 > > Merge tag 'drm-next-2019-09-18' of git://anongit.freedesktop.org/drm/drm Since you're able to bisect, any chance you could bisect into that merge, please? I hope Manasi and Lyude can look into this, but in the mean time bisecting to the actual regressing non-merge commit might be the quickest route to fixing this.
> Since you're able to bisect, any chance you could bisect into that merge, > please? I've not had to bisect into a merge before, do you have a quick guide you can link to?
Already fixed with commit e838bfa8e170415fa3cc8e83ecb171e809c0c422 Author: Ville Syrjälä <ville.syrjala@linux.intel.com> Date: Tue Sep 3 18:40:18 2019 +0300 Revert "drm/i915: Fix DP-MST crtc_mask" Looks like it hasn't made it into Linus's tree yet.
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