what's 2.5.96? Could you try git bisect?

(In reply to comment #1)
> what's 2.5.96? Could you try git bisect?
> 

I mean 'xf86-video-intel 2.5.96.0', a previous version from
git://anongit.freedesktop.org/xorg/driver/xf86-video-intel.

As it is only quite a minor bug, I am not going to try bisect, I am not used
doing this. Sorry.

These stripes appear only occasionly, they are not really disturbing!

The gray stripes occurring when scrolling Firefox still appear with version 
xf86-video-intel-2.6.0
In some apps characters are sometimes being rendered twice.

These features are also mentioned in bug #18138.

Driver : 
 - xf86-video-intel-2.6.0 (compiled for 1.5.3)
 - libdrm2 v.2.4.3+git+20090105+a8c5480-1 (Debian/experimental)
Kernel 2.6.26-1-686 (Debian/Sid v.2.6.26-13)

(In reply to comment #3)

Both issues (gray stripes appearing when scrolling and characters sometimes being rendered twice) are fixed when using Option "MigrationHeuristic" "greedy" 
in Section "Device" of xorg.conf

System:
Debian/Sid kernel 2.6.26-1 (Debian/Sid v.2.6.26-13)
Chipset: "852GM/855GM"
Driver:version = 2.6.1,compiled for 1.5.99.901
Libdrm2 v.2.4.3+git+20090105+a8c5480-1(Debian/experimental)

Does xserver master have this issue?

(In reply to comment #5)
> Does xserver master have this issue?
> 

I am sorry I can not compile the master version, get the following error:
---
i830_memory.c: In function ‘i830_allocator_init’:
i830_memory.c:539: error: ‘I915_SETPARAM_NUM_USED_FENCES’ undeclared (first use in this function)
i830_memory.c:539: error: (Each undeclared identifier is reported only once
i830_memory.c:539: error: for each function it appears in.)
make[4]: *** [i830_memory.lo] Error 1
make[4]: Leaving directory `/home/jos/tmp/xf86-video-intel-master/src'
make[3]: *** [all-recursive] Error 1
make[3]: Leaving directory `/home/jos/tmp/xf86-video-intel-master/src'
make[2]: *** [all] Error 2
make[2]: Leaving directory `/home/jos/tmp/xf86-video-intel-master/src'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/jos/tmp/xf86-video-intel-master'
make: *** [all] Error 2
---

current master require drm git master.

Created attachment 22706 [details]
xorg.0.log

Created attachment 22707 [details]
xorg.conf

(In reply to comment #7)
> current master require drm git master.
> 
OK, I compiled drm-master.tar.bz2 from http://cgit.freedesktop.org/mesa/drm/commit/ and copied the *.ko files to /lib/modules/2.6.26-1-686/kernel/drivers/char/drm
Now xf86-video-intel-master compiles without errors but it still doesn't work.
Xorg.0.log shows the following error:
(EE) Screen(s) found, but none have a usable configuration.
Fatal server error:
no screens found

Both issues (gray stripes appearing when scrolling and characters sometimes
being rendered twice) are fixed in xf86-video-intel-2.6.2

Option "MigrationHeuristic" "greedy" in Section "Device" of xorg.conf is no longer necessary.

System:
Debian/Sid kernel 2.6.26-1 (Debian/Sid v.2.6.26-13)
Chipset: "852GM/855GM"
Driver: version 2.6.2 compiled for 1.5.99.902 (xserver from Debian/experimental)
libdrm: v. 2.4.5

Using kernel 2.6.28 also no more screen corruptions!

Thanks for testing! Close this now.