ports/141021: Xorg strange behaviour: ~1/3 of the screen is darker, intel driver

[Davide]

>Number:         141021
>Category:       ports
>Synopsis:       Xorg strange behaviour: ~1/3 of the screen is darker, intel driver
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-ports-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Nov 30 11:50:01 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     Davide
>Release:        8.0
>Organization:
none
>Environment:
FreeBSD legend 8.0-RELEASE FreeBSD 8.0-RELEASE #1: Sun Nov 29 18:35:30 CET 2009     ocean at legend:/usr/obj/usr/src/sys/LEGEND  i386
>Description:
With Xorg in ports there's this problem (there was the same problem also with 7.2) it's like 1/3 of the LVDS is a little "darker" fading from lighter to darker, the problem seems to be more marcated (screen divided in 3 pieces starting from darker to lighter) when using LVDSFixed mode to False, so i think it's something related with lvds/drm.

Tried also disabling drm, doesn't change.
Tried also using latest intel (2.9.1) driver, doesn't change.
Tried with custom xorg.conf and default built-in configuration, doesn't change.

here's an extract from Xorg log that shows the chipset:

(--) PCI:*(0 at 0:2:0) Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller rev 3, Mem @ 0xb0080000/524288, 0xc0000000/268435456, 0xb0000000/262144, I/O @ 0x00001800/8, BIOS @ 0x????????/65536
(--) PCI: (0 at 0:2:1) Intel Corporation Mobile 915GM/GMS/910GML Express Graphics Controller rev 3

Would be nice to offer a separate Xorg r7.5 port (without substitution of r7.4 wich is stable), to see if with the new server works, or investigate in freebsd/drm to see why there's that strange problem.

I'm actually working with a kernel i configured/compiled, but problem is reproducible also with GENERIC.

thanks
>How-To-Repeat:
always reproducible.
start xorg and pay attention to the colors (using gnome with a blue background shows the difference really good.
>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: