[lug] XF86 multi-vid cards

D. Stimits stimits at attbi.com
Sun Dec 29 15:00:30 MST 2002

Paul Nowosielski wrote:

> Hi all,
> I'm try to set up multiple moniters/vid cards on my system.
> I'm using an NVIDIA GF-2 and an S3 card.
> Either card works fine independently BUT when I try to start them
> together it freezes X, keyboard, and mouse.One monitor goes black and
> the other will start the standard xinit screen.
> I have to SSH from another machine and kill X or do a hard restart to
> get the system functioning again.

If you can ssh in, you should be able to do (this is Redhat runlevel 
numbers, don't know what distro you have, check runlevels for your 
distro) an "init 3" to go to console-only multi-user mode, then "init 5" 
to get back (assuming you are using a login manager like xdm/gdm/kdm) to 
graphical mode without rebooting (it'd have to be a pretty serious 
problem to be able to ssh in but not restart graphical mode this way).

> the Nvidia card is AGP and the S3 is PCI. I've tried switching between
> the two cards in the bios with similar results.
>  I would like to run them as two separate monitors/windows managers and
> not use the xinerama option.
>  Also the Nvidia card has a TV out which I do not use, but I don't tell
> X this in the config file and don't think it has any thing to do with
> the problem, just thought I'd mention that.
> Does anyone have experience with duel monitor support who could advise
> me??
> Thanks!
> Paul Nowosielski

One suggestion when figuring it out, make sure hardware accel OpenGL is 
disabled. Getting it working without any hardware accel features prior 
to trying this...add accel after. Make sure all screen saver preferences 
are for non-OpenGL versions while testing. Also, disable any Xinerama 
features until you have it working without.

On top of what Steve mentioned on lspci, use lspci -v and see what 
possible IRQ or other conflicts could exist for the two video cards, 
compared side-by-side (AGP is a PCI device, and all PCI devices should 
be able to share IRQ, but in reality this does not seem to be entirely 
the way it is with all PCI devices, especially video card). You might 
even look at IRQ of NIC's or anything else that could be a problem.

You might also post the config file, Steve was mentioning PCI bus 
settings, it might be useful to see what else you have configured. E.G., 
two video cards requires displays 0:0.0 and 1:0.0 (meaning display 0 of 
server 0 and server 1), as opposed to 0:0.0 and 0:0.1 (meaning two 
displays of a single server).

D. Stimits, stimits AT attbi DOT com

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