Bug 90047

Summary: Graphics unstable with missing letter on Intel HD Graphics 5500 gen5 if SNA enabled
Product: xorg Reporter: John Doe <launchpad>
Component: Driver/intelAssignee: Chris Wilson <chris>
Status: RESOLVED FIXED QA Contact: Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity: major    
Priority: medium CC: gdm.impulse, launchpad
Version: unspecified   
Hardware: Other   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
Example of missing letters 1
none
Example of missing letters 2 none

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:
https://bugs.launchpad.net/xserver-xorg-video-intel/+bug/1432194

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.

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