Created attachment 27547 [details]
Xorg.0.log

Forwarding this bug from a Ubuntu reporter, Vincent Caron:
https://bugs.edge.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/373264

[Problem]
On i855, X boots to 1024x768 instead of the correct 1400x1050 resolution, and screen is corrupted with 1400px wide lines wrapping around.  This only occurs when the "Video expansion" BIOS feature is turned on (the factory default value).

This bug was first noticed in Jaunty but has also been tested on Karmic Alpha-2 with identical symptoms.

[Original Report]
I have a Dell 510m Inspiron laptop (Pentium M) with a i855 video chipset and a 1400x1050 LCD screen. With Ubuntu Hardy it worked like a charm, without any hack such as the infamous i195resolution. I just upgraded to Jaunty and the resolution is wrong: it looks lower (somewhat 1024x768) with still 1400px wide lines wrapping around, in an 'interlacing' style. Xrandr and xdpyinfo are sure they're running 1400x1050 and obviously the frame buffer is 1400x1050, although it's displayed in a quite unreadable "folded" fashion (it's not scrolling, it's wrapping).

I've tried various hacks (using FBDev, explicitly setting Virtual sizes, etc) to no avail.

I've updated the Dell BIOS from A09 to A11 to no avail.

But suddenly I got the idea to turn the "Video expansion" BIOS feature on, and the bug disappeared. This feature let the display automatically scale any resolution up to the screen size. The default (Dell factory) setting is on, but I usually turn it off on my Dell laptops, I prefer small and crisp text consoles than huge and blurry ones.

I guess we should be a small minority to experience this bug (BIOS tweaker + hawk eyes!). Although it looks like the intel video driver relies on some predefined state that's not always as expected.

Unfortunately the bug is still present with exact same symptoms on Karmic Alpha-2. I
disabled the "Video expansion" in BIOS, ran "Karmic alpha 2" live from
CD and saw the same problem. Attached is the Xorg.0.log.

# dpkg -l xserver-xorg-video-intel
ii xserver-xorg-video-intel 2:2.6.3-0ubuntu9 X.Org X server -- Intel i8xx, i9xx display driver

# cat /proc/mtrr
reg00: base=0x000000000 ( 0MB), size= 1024MB, count=1: write-back
reg01: base=0x040000000 ( 1024MB), size= 256MB, count=1: write-back
reg02: base=0x04ff00000 ( 1279MB), size= 1MB, count=1: uncachable
reg03: base=0x0feda0000 ( 4077MB), size= 128KB, count=1: write-through

# cat /etc/X11/xorg.conf
[... comments...]
Section "Monitor"
        Identifier "Configured Monitor"
EndSection

Section "Screen"
        Identifier "Default Screen"
        Monitor "Configured Monitor"
        Device "Configured Video Device"
EndSection

Section "Device"
        Identifier "Configured Video Device"
# Option "UseFBDev" "true"
EndSection

# ddcprobe
vbe: VESA 3.0 detected.
oem: Intel(r)852GM/852GME/855GM/855GME Graphics Chip Accelerated VGA BIOS
vendor: Intel Corporation
product: Intel(r)852GM/852GME/855GM/855GME Graphics Controller Hardware Version 0.0
memory: 832kb
mode: 1280x1024x256
mode: 1280x1024x64k
mode: 1280x1024x16m
mode: 1024x768x256
mode: 1024x768x64k
mode: 1024x768x16m
mode: 640x480x16m
mode: 800x600x64k
mode: 800x600x16m
mode: 640x480x256
mode: 800x600x256
mode: 640x480x64k
edid:
edid: 1 3
id: 0000
eisa: LPL0000
serial: 00000000
manufacture: 0 2004
input: analog signal.
screensize: 30 23
gamma: 2.200000
dpms: RGB, no active off, no suspend, no standby
dtiming: 1400x1050@70
dtiming: 1400x1050@70
monitorid: C1147150E07
monitorid: ����xP

[lspci]
00:00.0 Host bridge [0600]: Intel Corporation 82852/82855 GM/GME/PM/GMV Processor to I/O Controller [8086:3580] (rev 02)
     Subsystem: Dell Device [1028:0164]
00:02.0 VGA compatible controller [0300]: Intel Corporation 82852/855GM Integrated Graphics Device [8086:3582] (rev 02)
     Subsystem: Dell Device [1028:0164]