Re: Xorg tearing fix on Intel HD Graphics 4000

["Clément Lassieur" <clement@lassieur.org>]

Mark H Weaver <mhw@netris.org> writes:

> If we want to make UXA the default acceleration method for
> xf86-video-intel, I've attached a patch that accomplishes this without
> overriding auto-configuration.  Given the severity of the problems on
> the X200, I would be in favor of applying this patch to master.  The
> X200 is an important system for us because it is one of only two
> RYF-certified laptops.

On X200 this patch introduces the bug I described here:
https://bugs.freedesktop.org/show_bug.cgi?id=101620#c4

> FWIW, I do not notice any visually apparent difference in performance
> between UXA and SNA on the X200 for things like web browsing, watching
> videos, and running gnome-shell.  Nonetheless, I've seen reports that
> SNA performs significantly better than UXA, at least on newer Intel
> chips:
>
>   http://cynic.cc/blog/posts/sna_acceleration_vs_uxa/
>   https://ickle.wordpress.com/2013/10/02/and-over-in-the-red-corner/
>   https://www.reddit.com/r/archlinux/comments/17sy9l/intel_graphics_uxa_vs_sna/
>
> I would invite someone who cares about this to enhance
> 'xorg-configuration-file' in (gnu services xorg) to allow users to
> optionally specify which accel-method to use for each driver.

That would be useful indeed, I will have a look at it.