[NBLUG/talk] Dual Monitor configuration problem

Justin Thiessen thiessen at sonic.net
Mon Sep 29 10:31:01 PDT 2003

On Mon, Sep 29, 2003 at 10:06:29AM -0700, Kyle Rankin wrote:
> 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.

<snip Rob's problem>

> 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:
> http://greenfly.org/XF86Config-4-trihead
> 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
> use).

Kyle's description may be a little clearer than mine was.

Rob, if I were you I would try in this order:

(1) With the (AGP) Nvidia card set as primary in the BIOS, add the BusID 
    lines in XF86Config file for both the ATI and the Nvidia card.
(2) If (1) Doesn't work, switch the primary video adapter to be the (PCI)
    ATI card in the BIOS.  Leave the BusID lines in XF86Config.
(3) If neither (1) nor (2) work, switch your Nvidia driver as Kyle is 
    suggesting, and try them again.

Really, I think this should work.


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