Re: Xorg tearing fix on Intel HD Graphics 4000

[Mark H Weaver <mhw@netris.org>]

Andy Wingo <wingo@igalia.com> writes:

> On Wed 21 Jun 2017 09:55, Roel Janssen <roel@gnu.org> writes:
>
>> For a long time now, I have a tearing issue on GuixSD (parts of the
>> screen do not get updated while others do, resulting in dissapearing
>> text in Emacs).
>
> Thank you for this work!  I notice this since a month ago and haven't
> had time to delve into it.  Horrible stuff.
>
> I wonder if it makes sense to update the intel driver to see if it fixed
> it?  Then perhaps we could avoid the hack.  There are commits here that
> touch SNA and things that look like they could be relevant:
>
>   https://cgit.freedesktop.org/xorg/driver/xf86-video-intel/log/

It's a good idea, but we're already using HEAD (6babcf1) from their
repo, and have been since June 11 (guix commit e2de6bbdd5).  I can
confirm that this didn't solve the problem for me.

In the meantime, how would you feel about pushing the following commit
to master?  It would still allow the use of SNA by explicitly asking for
it in xorg.conf, but auto-configuration would choose UXA by default.

What do you think?

       Mark


From 745487d79dca402609200f67431ac19eaa99a4eb Mon Sep 17 00:00:00 2001
From: Mark H Weaver <mhw@netris.org>
Date: Sun, 25 Jun 2017 05:20:36 -0400
Subject: [PATCH] gnu: xf86-video-intel: Use UXA accel method by default.

* gnu/packages/xorg.scm (xf86-video-intel)[arguments]: Add #:configure-flags
with "--with-default-accel=uxa".
---
 gnu/packages/xorg.scm | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/gnu/packages/xorg.scm b/gnu/packages/xorg.scm
index d4da5d709..c6d194622 100644
--- a/gnu/packages/xorg.scm
+++ b/gnu/packages/xorg.scm
@@ -1,6 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2013, 2014 Andreas Enge <andreas@enge.fr>
-;;; Copyright © 2014, 2015 Mark H Weaver <mhw@netris.org>
+;;; Copyright © 2014, 2015, 2017 Mark H Weaver <mhw@netris.org>
 ;;; Copyright © 2014, 2015 Eric Bavier <bavier@member.fsf.org>
 ;;; Copyright © 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2015 Eric Dvorsak <eric@dvorsak.fr>
@@ -2849,7 +2849,8 @@ X server.")
                                     (string-prefix? "x86_64-" system)))
                %supported-systems))
       (arguments
-       '(#:phases (modify-phases %standard-phases
+       '(#:configure-flags '("--with-default-accel=uxa")
+         #:phases (modify-phases %standard-phases
                     (add-after 'unpack 'bootstrap
                       (lambda _
                         (zero? (system* "autoreconf" "-vfi")))))))
-- 

2.13.1