[NBLUG/talk] Dual Monitor configuration problem

Kyle Rankin kyle at nblug.org
Mon Sep 29 10:07:01 PDT 2003

On Sun, Sep 28, 2003 at 07:13:49PM -0700, Rob Orsini wrote:
> I am having problems getting both monitors working with a new RH9 box 
> of mine.  I have two video cards: Nvidia (AGP) and a ATI (PCI).  I have 
> confirmed that each card/monitor works on it's own with my system by 
> switching the bios video setting between PCI and AGP.  I think my 
> XF86config file is in pretty good shape in terms of the required 
> sections. My current theory is that my system is looking in the wrong 
> place for the second video card, but I really don't know what's going 
> on.
> Here are two lines that stood out to me from the XFree86.log file:
> (II) ATI:  Candidate "Device" section "Videocard1".
> (WW) ATI:  PCI/AGP Mach64 in slot 2:0:0 could not be detected!
> Do I need to tell X exactly where to look for each video card?
> <my files>
> Here is my config file which starts without any errors (EE) lines:
> http://www.orsini.us/X/XF86Config
> and here is the current contents of my XFree86.0.log file:
> http://www.orsini.us/X/XFree86.0.log
> and finally the output of the 'lspci' command:
> http://www.orsini.us/X/lspci
> </my files>
> Thanks,
> Rob

There can be some tricky issues when trying to get ATI and Nvidia cards to
behave in a dual-head mode.  What you are experiencing right now we can
call "duel-head mode" because each card is fighting to be the main card.

One thing that sometimes works is to use the BusID configuration option for
both cards, for instance, my setup is a bit weird (it was a dual-head
Twinview setup on a single nvidia card, plus a third head on a Matrox card
using xinerama) but you can see the gist here:

basically something like:
BusID   "PCI:1:0:0"
for the nvidia and
BusID   "PCI:2:0:0"
for the ATI card.

Another thing I would try is to experiment with both the "nv" nvidia driver
and the "nvidia" proprietary one, and see if one or the other are
better-behaved in xinerama.

Your last option would be to drop by HSC and get a $10 2mb Matrox card,
with which you can disable VGA BIOS on the card itself.  Those cards work
like a charm with xinerama (provided it supports the resolution you want to

Kyle Rankin
NBLUG President
The North Bay Linux Users Group
IRC: greenfly at irc.freenode.net #nblug 
kyle at nblug.org

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