Bug 35466

Summary:	Screen corruption with 2.6.38 and i855
Product:	DRI	Reporter:	Cesare Leonardi <celeonar>
Component:	DRM/Intel	Assignee:	Chris Wilson <chris>
Status:	CLOSED FIXED	QA Contact:
Severity:	normal
Priority:	medium	CC:	jbarnes
Version:	unspecified
Hardware:	x86 (IA32)
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:

Description Cesare Leonardi 2011-03-20 08:02:29 UTC

With 2.6.38 my screen shows many corruptions, as i already described here:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=619022

Here you can find also an attachment that shows the problem.

Some information not reported in Debian bug report:
xserver-xorg 1:7.6+4
xserver-xorg-core 2:1.9.4-90
xserver-xorg-video-intel 2:2.14.0-4
libdrm-intel1 2.4.23-3

Let me know if you need more info.

Cesare.

Comment 1 Chris Wilson 2011-03-20 08:06:12 UTC

Update your userspace to include:

xf86-video-intel commit d21d781466785c317131a8a57606925867265dc8
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Tue Feb 22 18:31:44 2011 +0100

    Fix relaxed tiling on gen2
    
    Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

[2.14.901], but watch out for bug 35460.

Comment 2 Cesare Leonardi 2011-03-20 08:20:57 UTC

(In reply to comment #1)
> [2.14.901], but watch out for bug 35460.

Thank you very much for the really fast reply, Chris.
So, if i have understood correctly:
- 2.6.38 require at least an intel driver >= 2.14.901
- even if the driver is updated there are still corruption problems (#35460) on which you are working on.

So while waiting for updated intel driver, for an i855 user should be wise to use an older kernel.

Am i correct?

Cesare.

Comment 3 Chris Wilson 2011-03-20 08:28:08 UTC

Or an older userspace. I introduced lazy fencing as I developed the kernel patches, about 6 months ago. It was only with the general release of the kernel enabling patches that the gen2 bug in the userspace code was discovered.

If I had sufficient foresight I would have also added a module option to disable relaxed fence allocation in case of emergencies such as this. :(

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