bug#38199: 27.0.50; [Cairo] Display artifacts (small vertical colored bars)

[Bastian Beischer]

On Fri, Nov 15, 2019 at 8:59 AM Eli Zaretskii <eliz@gnu.org> wrote:
>
> > From: Bastian Beischer <bastian.beischer@gmail.com>
> > Date: Thu, 14 Nov 2019 23:30:32 +0100
> > Cc: 38199@debbugs.gnu.org
> >
> > > Did you try to disable "advanced" or "optimization" features of your
> > > display driver software?  Or upgrade it to a newer version?  The
> > > artifacts your screenshot shows don't look like something Emacs could
> > > produce.
> >
> > You are right: It could well be a cairo library or driver issue. I am
> > using the default optimized builds from the Arch Linux x86_64
> > repository, which means:
> >
> > cairo: 1.17.2+17+g52a7c79fd-2
> > Xorg: 1.20.5-4
> > mesa: 19.2.3-2
> > linux: 5.3.11.1-1
> >
> > My GPU is NVIDIA Geforce GTX 285 (nouveau kernel driver, combined with
> > modesetting / glamor). Should I report a bug against cairo?
>
> Maybe; it could also be a bug in the NVIDIA drivers.  So before
> reporting a Cairo bug, I'd look at the settings of your video driver,
> and if there are any "optimization" features there, try to disable
> them.

I have now confirmed the bug on a different PC with an Intel GPU. It
persists when using modesetting and when using xf86-video-intel as
drivers there. So I think it's unlikely that it is a bug in the
driver.

I will now open a cairo issue.