Bug 45009

Summary:	minor graphical glitches
Product:	pixman	Reporter:	Michael Biebl <mbiebl>
Component:	pixman	Assignee:	Søren Sandmann Pedersen <soren.sandmann>
Status:	RESOLVED FIXED	QA Contact:	Søren Sandmann Pedersen <soren.sandmann>
Severity:	normal
Priority:	medium	CC:	kibi
Version:	other
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:
Attachments:	screenshot before screenshot after Xorg log

Description Michael Biebl 2012-01-20 14:37:40 UTC

Version: 0.24.2
Bug-Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=656682

Since the upgrade from 0.24.0 → 0.24.2 I have minor graphical glitches most notably in gtk2 apps. Attached is a screenshot for thunderbird using 0.24.0 (before) and 0.24.2 (after).
Reverting ee500cb2b1abf04ba40a8abfe358f6211d6078d1 fixed those glitches for me.

Comment 1 Michael Biebl 2012-01-20 14:38:24 UTC

Created attachment 55872 [details]
screenshot before

Comment 2 Michael Biebl 2012-01-20 14:39:05 UTC

Created attachment 55873 [details]
screenshot after

Comment 3 Søren Sandmann Pedersen 2012-01-20 16:47:30 UTC

Thanks for the bug report. 

Is this affecting the X server or cairo on the client? Ie., after reverting this commit, is it enough to restart thunderbird, or do you have to restart the X server too?

If restarting the X server is necessary, which graphics driver and version are you using?

Comment 4 Søren Sandmann Pedersen 2012-01-20 17:56:06 UTC

Also, what version of cairo are you using?

Comment 5 Michael Biebl 2012-01-20 23:56:27 UTC

(In reply to comment #3)
> Thanks for the bug report. 
> 
> Is this affecting the X server or cairo on the client? Ie., after reverting
> this commit, is it enough to restart thunderbird, or do you have to restart the
> X server too?
> 
> If restarting the X server is necessary, which graphics driver and version are
> you using?

I had to restart the X server. Simply restarting the application was not sufficient. I'm using the intel driver (on a X220 with Sandybridge graphics hardware). The relevant Debian versions are:

xserver-xorg-core: 2:1.11.3.901-2
xserver-xorg-video-intel: 2:2.17.0-1
libcairo2: 1.10.2-6.2

I've also attached the Xorg.0.log

Comment 6 Michael Biebl 2012-01-20 23:56:58 UTC

Created attachment 55891 [details]
Xorg log

Comment 7 Søren Sandmann Pedersen 2012-01-24 06:31:39 UTC

I can't reproduce this bug, not even with the 2.17.0 driver on Sandy Bridge hardware. 

Please try the "trapdebug" branch of this repository:

    git://people.freedesktop.org/~sandmann/pixman

and see if it prints debug spew about invalid trapezoids to the X log file. If it does, please paste some of the spew here.

Also, if you have a second machine and you can ssh in and set a breakpoint on the "print_trap" function to get a backtrace to find out what is generating the invalid traps, that would be helpful.

Comment 8 Søren Sandmann Pedersen 2012-01-25 11:04:03 UTC

It turns out that cairo does generate trapezoids where top is strictly above the edges or bottom is strictly below.  It doesn't look like it's feasible to consider such trapezoids invalid.

Comment 9 Søren Sandmann Pedersen 2012-01-31 06:20:23 UTC

Fixed in master by reverting that commit. An 0.24.4 release will be coming soonish.

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