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Bug 739865 - Gnome 3.10 leaves visual artifacts on displays connected to a non-primary GPU
Gnome 3.10 leaves visual artifacts on displays connected to a non-primary GPU
Status: RESOLVED INCOMPLETE
Product: gnome-shell
Classification: Core
Component: general
3.10.x
Other Linux
: Normal normal
: ---
Assigned To: gnome-shell-maint
gnome-shell-maint
Depends on:
Blocks:
 
 
Reported: 2014-11-10 08:17 UTC by Dominic Chambers
Modified: 2019-09-28 21:26 UTC
See Also:
GNOME target: ---
GNOME version: ---



Description Dominic Chambers 2014-11-10 08:17:00 UTC
In Fedora 19 and Ubuntu 13.04 (Gnome 3.8) it's possible to use displays that are connected to a non-primary GPU with the help of the xrandr command, for example:

  xrandr --setprovideroutputsource Intel nouveau
  xrandr --auto

But in Fedora 20 and Ubuntu 14.04 (Gnome 3.10) these displays become unusably slow, with visual artifacts being left around. I know it's not related to the version of the kernel since Fedora 19 initially shipped with kernel 3.9, but is now up to 3.14, and continues to work just fine. It's also not the display manager, since I've seen the same problem using both LightDM (Ubuntu 14.04) and GDM (Gnome Ubuntu 14.04).

There is a related but separate bug reported by the Arch Linux community:

  https://bbs.archlinux.org/viewtopic.php?pid=1334330

but where in this case the visual artifacts appear only temporarily. That the work-arounds suggested within that forum don't work in this case also suggest that this is a distinct bug.
Comment 1 Dominic Chambers 2014-11-10 08:43:17 UTC
I just tried recording a video of the problem happening (using SimpleScreenRecorder), but strangely the act of recording it made the problem much better, with almost no artifacts occurring. I'll try again tonight with a different screen recorder and see if I can catch it. BTW, I'm using a Lenovo T430 in case that is a factor.
Comment 2 Dominic Chambers 2014-11-10 21:02:58 UTC
I just tried a different desktop video capture program (RecordMyDesktop this time). Like SimpleScreenRecorder, the act of capturing reduced the number of artifacts I see, though overall I see more artifacts with RecordMyDesktop than when using SimpleScreenRecorder. In both cases however, none of the artifacts I see on the monitors are actually visible in the video capture, so I still have no video I can share with you.

It therefore seems like a race condition, and perhaps it's always existed as a latent bug, but where Gnome 3.10 merely exacerbates it? Or, were there substantive changes in the way rendering was done in Gnome 3.10 that may have triggered this problem?
Comment 3 Dominic Chambers 2014-11-17 20:19:44 UTC
Is there any more information I can provide to help progress this issue?
Comment 4 André Klapper 2015-04-17 21:24:10 UTC
Dominic: Does this still happen in 3.16?
Comment 5 André Klapper 2019-09-28 21:26:09 UTC
> Dominic: Does this still happen in 3.16?

Closing this bug report as no further information has been provided. Please feel free to reopen this bug report if you can provide the information that was asked for in a previous comment.
Thanks!