Bug 14437

Summary: [855GM 2.2.0.90] regression: screen flickering in green
Product: xorg Reporter: Jos van Wolput <wolput>
Component: Driver/intelAssignee: Wang Zhenyu <zhenyu.z.wang>
Status: RESOLVED FIXED QA Contact: Xorg Project Team <xorg-team>
Severity: normal    
Priority: medium CC: hong.liu, jbarnes
Version: 7.3 (2007.09)Keywords: regression
Hardware: x86 (IA32)   
OS: Linux (All)   
URL: http://homepages.onsneteindhoven.nl/~wolput
Whiteboard:
i915 platform: i915 features:
Bug Depends on:    
Bug Blocks: 13493    
Attachments:
Description Flags
xorg.conf
none
xorg.0.log none

Description Jos van Wolput 2008-02-08 21:15:41 UTC
Created attachment 14228 [details]
xorg.conf

Package: xserver-xorg-video-intel
Version: 2:2.2.0.90-3 (Debian Sid)
kernel: 2.6.24-1-686
Chip: Intel Corporation 82852/855GM Integrated Graphics Device

I sporadically get some green flickering after upgrading to version 2.2.0.90-3
Seems to be a regression since there is no flickering when using xserver-xorg-video-intel_2.2.0-1+exa_i386.deb or xserver-xorg-video-intel_2.2.0+git20080107-1_i386.deb

Regards,
Jos van Wolput
Comment 1 Jos van Wolput 2008-02-08 21:17:04 UTC
Created attachment 14229 [details]
xorg.0.log
Comment 2 Wang Zhenyu 2008-02-11 07:01:18 UTC
Could you help to git bisect which commit could cause the problem you see?
Comment 3 Jos van Wolput 2008-02-11 07:55:34 UTC
bugzilla-daemon@freedesktop.org wrote:
> 
> --- Comment #2 from Wang Zhenyu <zhenyu.z.wang@intel.com>  2008-02-11 07:01:18 PST ---
> Could you help to git bisect which commit could cause the problem you see?
> 
> 
Sure I want to help but I don't understand "bisect", how to "git bisect"?
I am a physicist, not a programmer!

Jos v.W.
Comment 4 Jos van Wolput 2008-02-11 18:22:38 UTC
bugzilla-daemon@freedesktop.org wrote:
> --- Comment #2 from Wang Zhenyu <zhenyu.z.wang@intel.com>  2008-02-11 07:01:18 PST ---
> Could you help to git bisect which commit could cause the problem you see?
> 
I got git-clone git://anongit.freedesktop.org/git/xorg/driver/xf86-video-intel
but that's the version that gives some flickering.
Please tell me which versions to git bisect and how to proceed, I never have used git bisect!

祝你新年快乐!
Jos v.W.
Comment 5 Wang Zhenyu 2008-02-13 08:20:26 UTC
(In reply to comment #4)
> 祝你新年快乐!

Thank you! You too! ;)

Here's the doc for git-bisect:
http://www.kernel.org/pub/software/scm/git/docs/git-bisect.html

If you failed to successfully bisect it, I'll try to reproduce it on the 855gm
in my office later.

Comment 6 Jos van Wolput 2008-02-14 03:18:28 UTC
bugzilla-daemon@freedesktop.org wrote:
> http://bugs.freedesktop.org/show_bug.cgi?id=14437
> If you failed to successfully bisect it, I'll try to reproduce it on the 855gm
> in my office later.
> 
> 

Here is the result of bisect:
---
jos@jewel:~/xf86-video-intel$ git bisect start -- arch/i386
jos@jewel:~/xf86-video-intel$ git bisect bad xf86-video-intel-2.2.0.90
jos@jewel:~/xf86-video-intel$ git bisect good xf86-video-intel-2.2.0
Bisecting: -1 revisions left to test after this
[4a2b0f340357c4ca58dc9586fad1337b83966362] Fix typo in 1920x1080 resolution entry
---
The green flickering appears especially in the right part of the screen when viewing pictures.
It is reproducible whenever I install v. 2.2.0.90 and doesn't occur with v.2.2.0

Comment 7 Wang Zhenyu 2008-02-17 06:41:48 UTC
(In reply to comment #6)

> jos@jewel:~/xf86-video-intel$ git bisect start -- arch/i386

oh, that git-bisect manual page's example is for linux kernel, as arch/i386
(which is gone) used for. For intel video driver, no dir should be needed.

> jos@jewel:~/xf86-video-intel$ git bisect bad xf86-video-intel-2.2.0.90
> jos@jewel:~/xf86-video-intel$ git bisect good xf86-video-intel-2.2.0
> Bisecting: -1 revisions left to test after this
> [4a2b0f340357c4ca58dc9586fad1337b83966362] Fix typo in 1920x1080 resolution
> entry

This commit seems just following 2.2.0 version dump, and shouldn't affect your problem...
Comment 8 Jos van Wolput 2008-02-18 07:43:23 UTC
bugzilla-daemon@freedesktop.org wrote:
> http://bugs.freedesktop.org/show_bug.cgi?id=14437
> --- Comment #7 from Wang Zhenyu <zhenyu.z.wang@intel.com>  2008-02-17 06:41:48 PST ---
> (In reply to comment #6)
> 

I have found that the flickering originates from xf86-video-intel-2.2.0.90/src/i830_display.c.
When replacing (around line 1727)
	    if ((INREG(LVDS) & LVDS_CLKB_POWER_MASK) == LVDS_CLKB_POWER_UP)
		clock.p2 = I8XX_P2_LVDS_SLOW;
	    else
		clock.p2 = I8XX_P2_LVDS_FAST;
by
	    clock.p2 = 14;
as in the previous version 2.2.0, the flickering no longer occurs.
There must be a reason why this was changed, but it obviously causes a regression!
Comment 9 Wang Zhenyu 2008-02-18 16:44:58 UTC
oh, thanks. Add Hong to cc.
Comment 10 Wang Zhenyu 2008-02-18 16:55:10 UTC
oops, my change to Hong's patch got reverse effect...fix patch is pushed to master.
Comment 11 Jos van Wolput 2008-02-18 21:22:10 UTC
bugzilla-daemon@freedesktop.org wrote:
> http://bugs.freedesktop.org/show_bug.cgi?id=14437
> 
> 
> 
> 
> 
> --- Comment #10 from Wang Zhenyu <zhenyu.z.wang@intel.com>  2008-02-18 16:55:10 PST ---
> oops, my change to Hong's patch got reverse effect...fix patch is pushed to
> master.
> 
> 
I got your last commit, no more flickering! :)

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