Bug 29239

Summary:	Corrupted medium/heavy blur, light blur works
Product:	Mesa	Reporter:	Andreas Demmer <mail>
Component:	Drivers/DRI/i915	Assignee:	Eric Anholt <eric>
Status:	RESOLVED FIXED	QA Contact:
Severity:	normal
Priority:	medium	Keywords:	NEEDINFO
Version:	7.5
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:
Attachments:	Xorg logfile with Mesa master

Description Andreas Demmer 2010-07-25 03:44:57 UTC

I use the latest xf86-driver-intel i915 with my Intel Arrandale card on openSUSE 11.3 on kernel 2.6.34 with Xorg 7.5.

I am running KDE SC 4.5. Its window manager KWin has a blur effect which works fine while using slight blur settings. When increasing blur strength, the blur corrupts.

Screenshot of correct rendering of light blur:
http://img689.imageshack.us/img689/4499/lightblurcorrect.jpg

Screenshot of corrupted rendering of medium blur:
http://img708.imageshack.us/img708/9138/mediumblurcorrupted.jpg

I talked to the KWin maintainers and they told me that this is likely an issue with the mesa driver in combination with my hardware as the blur effect works fine on other combinations.

Here you can find the implementation of the blur effect: http://websvn.kde.org/trunk/KDE/kdebase/workspace/kwin/effects/blur/

Comment 1 Eric Anholt 2010-07-26 18:29:53 UTC

Could you retest with Mesa master?  I can't tell for sure without the output of the app under INTEL_DEBUG=vs,wm, but I may have fixed this recently with the glsl-max-varyings fixes.

Comment 2 Andreas Demmer 2010-07-27 00:16:40 UTC

I built Mesa from Git and now I have no blur at all! Though KWin desktop effects still work. KWin complains that it could not enable the blur effect (because it is not supported).

I did the following steps:
1. git clone
2. make linux-dri-x86-64
3. copied all *_dri.so files to /usr/lib64/dri
4. copied all lib* files to /usr/lib64
5. copied egl folder to /usr/lib64/egl
6. ldconfig

Am I missing something? I also attached my Xorg logfile after installing Mesa master.

Comment 3 Andreas Demmer 2010-07-27 00:17:10 UTC

Created attachment 37410 [details]
Xorg logfile with Mesa master

Comment 4 Andreas Demmer 2010-08-01 23:41:45 UTC

Any news on this?

Comment 5 Eric Anholt 2010-08-30 11:28:44 UTC

the environment variable MESA_GLSL=dump can be useful in finding out why the shader failed to compile (if that's what happened, it's hard to know when you don't include the error message), and I still want the output with INTEL_DEBUG=vs,wm.  Both at the same time, really.

Comment 6 Eric Anholt 2010-10-14 17:12:22 UTC

OK, I think this is fixed now, tested using the glsl-kwin-blur piglit test that was generated to cover this.  One of the failures fixed would have been "as you increased blur size, you started getting garbage values."

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