Whilst trying to reproduce bug 28811 on my t61, I found (connecting DVI and VGA to the same 1920x1080 panel): xrandr --output LVDS1 --off --output VGA1 --off --output DVI1 --mode 1024x768 # works xrandr --output LVDS1 --off --output VGA1 --mode 1024x768 --output DVI1 --off # works xrandr --output LVDS1 --off --output VGA1 --mode 1024x768 --output DVI1 --mode 1024x768 # both DVI and VGA is out-of-sync Unsure where the bug lies, if actually a bug. Repeating the test for different resolutions works, then going back to 1024x768 worked. Hmm.
Lowest priority until I can reproduce reliably and figure out what is going on.
Created attachment 37820 [details] dmesg The issue appears connected with sharing the crtc between the two encoders.
See also bug 16777.
Bring on the atomic multiple-crtc modesetting!
Atomic modesetting across mutliple crtcs is Jesse's pet-peeve.
What if you prevent CRTC sharing by setting the clone_mask for VGA and/or DVI to prevent it? Pipe sharing hasn't been well validated for a long time, so we shouldn't allow it much these days...
Prod for retesting or closing ... If it's indeed a sharing bug, the recent pile of "disallow sharing with SDVO" might have helped. Otherwise I think we should just disable sharing some more - it's busted for sure.
Still fails.
Created attachment 70007 [details] dmesg
Checked dmesg, it's indeed setting up a shared pipe for VGA and DVI. I guess we should just throw in the tovel and declare SDVO as non-shareable. Let me stitch together a patch.
Created attachment 70009 [details] [review] disable cloning on sdvo Disabling sdvo cloning completely. It's broken. Patch applies on top of -nightly due to a sdvo cloning-disable patch which is only in -fixes.
That does the trick, so Tested-by: Chris Wilson <chris@chris-wilson.co.uk> I can still dream that we could share the resources, but it is not worth fighting for.
commit e506d6fde50e0a737234892eda31708692bdda29 Author: Daniel Vetter <daniel.vetter@ffwll.ch> Date: Tue Nov 13 17:24:43 2012 +0100 drm/i915: disable cloning on sdvo After the recent pile of disable-cloning patches, e.g. commit e3b86d6941c7e5f90be05d986fce1fcb40c68d6b Author: Egbert Eich <eich@suse.de> Date: Sat Oct 13 14:30:15 2012 +0200 DRM/i915: Don't clone SDVO LVDS with analog and a bug report from Chris Wilson indicating that cloning doesn't even work for DVI-SDVO and native VGA, let's just disable cloning on sdvo encoders completely. v2: Update the comment in the code as discussed with Paulo Zanoni.
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