upgrade from debian etch to debian testing (lenny) results in garbled screen

[Alex Deucher]

On Thu, Jan 1, 2009 at 5:15 AM, Hartmut Niemann <Hartmut.Niemann at gmx.de> wrote:
> Am Dienstag 30 Dezember 2008 schrieb Alex Deucher:
>> On Sun, Dec 28, 2008 at 2:31 PM, Hartmut Niemann <Hartmut.Niemann at gmx.de> wrote:
>> > Hello everybody!
>> > I upgraded the following system from debian etch to current testing:
>> >
>> > AMD Athlon(tm) XP 2600+
>> > VIA KT400 chipset
>> > ATI Technologies Inc RV280 [Radeon 9200 SE] (rev 01) (according to lspci)
>> > BENQ G2400W (1920x1200)
>> >
>> > and the xorg.conf that worked fine with debian etch results in a totally distorted screen,
>> > with diagonal stripes that have about the color the screen should have
>> > (light blue for the login screen, and the main colors of the background picture
>> > after a more or less blind login seemed right) Like the rendering engine
>> > has a different opinion how many pixels are in a line from the output stage.
>> >
>> > Versions of debian packages:
>> > xserver-xorg-video-ati    1:6.9.0-1+
>> >
>>
>> Do you have the same monitor plugged into both the DVI and VGA ports
>> on your card?  If so, remove one or the other as the monitor may be
>> getting confused.  Also comment out or remove the monitor section in
>> your config because it maybe overriding the 1920x1200 mode from your
>> monitor's EDID with your modeline.  I suspect your monitor doesn't
>> like the 193 Mhz pixel clock in your modeline.  the preferred clock
>> from your monitor's EDID is 154 Mhz.
>
> Hello Alex,
> thank you for your reply and the hints you gave.
> I commented the monitor section out and checked that the VGA cable is removed,
> which gave me the same distorted picture I described above
>
> http://www.nieleute.de/Xorg.0.log.agpmode
>
> The monitor reported correctly 1920x1200 at 60Hz and, as before, I had a sharp and
> correctly moving cursor.
>
> And then I remembered a hint you gave me about a year ago, and that helped:
>>If it's an AGP card, try forcing it
>>into PCI mode (Option "BusType" "PCI").
> This gives me a working 1920x1200 at 60Hz. Yeah!
> http://www.nieleute.de/Xorg.0.log.pcimode
> http://www.nieleute.de/xorg.conf.pcimode
>
> Is this a broken mainboard - graphics combination?

Sounds like a bad AGP mode.  We can add a quirk to the driver to work
around it.  Try the following option in the device section of your
xorg.conf:

Option "AGPMode" "x"
where x = 1 or 2 or 4 or 8.

When you find a combination that works send me your xorg log and the
output of lspci -vn and I'll add a quirk to the driver.

Alex