Bug 90047 - Graphics unstable with missing letter on Intel HD Graphics 5500 gen5 if SNA enabled
Summary: Graphics unstable with missing letter on Intel HD Graphics 5500 gen5 if SNA e...
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/intel (show other bugs)
Version: unspecified
Hardware: Other Linux (All)
: medium major
Assignee: Chris Wilson
QA Contact: Intel GFX Bugs mailing list
Depends on:
Reported: 2015-04-16 07:33 UTC by John Doe
Modified: 2015-04-23 09:28 UTC (History)
2 users (show)

See Also:
i915 platform:
i915 features:

Example of missing letters 1 (32.51 KB, text/plain)
2015-04-16 07:33 UTC, John Doe
no flags Details
Example of missing letters 2 (46.03 KB, text/plain)
2015-04-16 07:33 UTC, John Doe
no flags Details

Description John Doe 2015-04-16 07:33:02 UTC
Created attachment 115108 [details]
Example of missing letters 1

Dear Intel graphic Team, Chris,

Copied from a Ubuntu bug report at:

As the issue doesn't looks like others, please find attached some screenshots.
A workaround is to enable UXA instead of SNA. Tested with last drivers from 01.org.

Best regards.
Comment 1 John Doe 2015-04-16 07:33:24 UTC
Created attachment 115109 [details]
Example of missing letters 2
Comment 2 Chris Wilson 2015-04-16 07:42:26 UTC
Fixed several months ago in upstream, I even warned ubuntu about the bug...
Comment 3 John Doe 2015-04-16 08:13:34 UTC
Thank you Chris for your response; Now I have to convince someone from Ubuntu.
Comment 4 John Doe 2015-04-16 08:18:08 UTC
Do you remember the bug ID?
Comment 5 Chris Wilson 2015-04-16 08:20:37 UTC
I informed tjaalton on irc about which patches he was missing...

In particular you need commit 7a9bdadd71730adc5266bc6758982abec5917b93
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Wed Oct 22 19:31:10 2014 +0100

    sna/gen8: Clamp URB allocations for GT3
Comment 6 gdm.impulse 2015-04-23 06:24:23 UTC
Does that patch apply to the HD Graphics 5500 (GT2) as well?  I'm seeing the same issue running on Ubuntu 15.04.  I downloaded the source package for the Intel drivers I'm currently running, and I'm seeing that patch already applied.
Comment 7 Chris Wilson 2015-04-23 06:50:07 UTC
Just check upstream first, if you still have issues you have an entirely different bug.
Comment 8 gdm.impulse 2015-04-23 09:23:32 UTC
FWIW, I tested the driver as of commit 4fdd3a7 and was still seeing the same issues.  Turns out if I run a glx program (e.g. compton), I can't reproduce the issue.  I also use awesomewm which doesn't come with a compositing window manager, however I noticed that I wasn't able to reproduce the issue with Unity or Gnome which both do include compositing window managers.  The other thing I noticed is that if I didn't use a compositing window manager but opened glxgears after the screen corruption, the screen would be restored to normal.
Comment 9 Chris Wilson 2015-04-23 09:28:57 UTC
That sounds more like a different kernel bug if a pageflip is flushing the scanout.

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.