Bug 42677

Summary:

Setting NO_COMPOSITE results in rendering corruptions [SNA]

Product:

xorg

Reporter:

Clemens Eisserer <linuxhippy>

Component:

Driver/intel

Assignee:

Chris Wilson <chris>

Status:

RESOLVED FIXED

QA Contact:

Xorg Project Team <xorg-team>

Severity:

normal

Priority:

medium

Version:

git

Hardware:

Other

OS:

All

Whiteboard:

i915 platform:

i915 features:

Attachments:

Description	Flags
screenshot of glyph corruption	none

Description Clemens Eisserer 2011-11-07 11:18:36 UTC

Created attachment 53263 [details]
screenshot of glyph corruption

When enabling NO_COMPOSITE, I get rendering corruptions very similar to those mentioned in bug 42663.

intel i945GM
intel-git
libdrm-2.4.27
pixman-0.23.8
linux-3.1.0
xorg 1.11.1

Comment 1 Chris Wilson 2011-11-07 11:23:34 UTC

This is a little more of a wontfix as it should only be possible to trigger that path with a GPU hang. I'll of course look to see if there is a genuine bug, but I suspect it is hitting an intentional discard path.

Comment 2 Clemens Eisserer 2011-11-07 11:25:23 UTC

I also don't care wether its fixed or not, just thought reporting it does no harm (except maybe you getting tired ;)).

Comment 3 Chris Wilson 2011-11-07 11:47:42 UTC

No worries. :)

It has just been a bad day, fighting against a headache whilst trying to find the 16bit overflow....

Comment 4 Chris Wilson 2011-11-07 14:56:22 UTC

So this turns out not to be so innocuous after all, thanks!

commit 5ba8ba7421e36bcdf83e84423595326939dbe7cd
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Mon Nov 7 22:55:10 2011 +0000

    sna: Avoid overwriting an upload buffer during readback
    
    Reported-by: Clemens Eisserer <linuxhippy@gmail.com>
    Buzilla: https://bugs.freedesktop.org/show_bug.cgi?id=42677
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

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