Two Radeon Cards, Dell Dimension, Linux and x.org

[Thorsten Becker]

Xorg 7.0.0, kernel 2.6.15-gentoo-r1

Hello,

To create a dual seat system I bought a Readeon 7000 PCI card for my Dell 
Dimension 4550, which has a Radeon 9700 already installed. The Problem is: I 
can only get one card to work at a time. Trying to start an X server on the 
"wrong card" results in locking up the system (it doesn't even write an 
Xorg.0.log logfile)

What I tried so far:

BIOS settings: The somewhat crippled BIOS in the dell system only has a few 
settings that could be relevant: "Primary Video Controller" is one of them, 
it can be set to AGP or Auto. 
If set to AGP, the AGP card works, the vga console is shown on the Monitor 
that is connected to that card. I can start an X server for that card, and it 
works.
If set to Auto, the PCI card works, and I can start an X server for that card.

But If it is set to AGP, and I try to start an X server for the PCI card, the 
result is  a complete system lockup, same the other way round.

I tried to get some useful debugging output by starting X for the "wrong card" 
via ssh and get some information via the -verbose Option. Such a log can be 
found here:
http://www.tuxdesk.de/Xremote.log

The xorg.conf can be found here:
http://www.tuxdesk.de/xorg.conf.2120

One time a short Xorg log was written. I out it here:
http://www.tuxdesk.de/Xorg.0.log

When I start X whith the -verbose option, the last thing I can see is always

(II) RADEON(0): initializing int10
(--) RADEON(0): Chipset: "ATI Radeon VE/7000 QY (AGP/PCI)" (ChipID = 0x5159)
(--) RADEON(0): Linear framebuffer at 0xe0000000
(--) RADEON(0): VideoRAM: 8192 kByte (64 bit SDR SDRAM)
(II) RADEON(0): Color tiling enabled by default
(II) Loading /usr/lib/xorg/modules/libddc.so
(II) Module ddc: vendor="X.Org Foundation"
        compiled for 7.0.0, module version = 1.0.0
(II) Loading /usr/lib/xorg/modules/libi2c.so
(II) Module i2c: vendor="X.Org Foundation"
        compiled for 7.0.0, module version = 1.2.0
(II) RADEON(0): I2C bus "DDC" initialized.
                                 
and sometimes I see Messages like 
"Requesting insufficient memory window!: start: 0xff800000
end: 0xff9fffff size 0xff820000"

The cards work simultaneously with the other OS, so I thought they sould work 
with xorg too.

I would be happy to get some input on what to try next, which options I might 
have overlooked and what I could try to get a more meaningful debugging 
output.

Thanks,
Thorsten