Re: Dual head initialization

[Helge H. <hel...@ai...>]

Joshua Reed wrote:

>-----BEGIN PGP SIGNED MESSAGE-----
>Hash: SHA1
>
>YEAH!  I finally got a dual head system set up and running with a Matrox
>G450 card.
>My only question is if the issue of framebuffer re-initalization when
>exiting X was ever resolved?
>When I Exit X on the primary head (a mga device) it grabs the frame
>buffer for the secondary head (the fbdev device)  A switch to vt8 and
>back to vt7 fixes this, but most of my roommates are not so
>understanding of this quirk.
>is there
>A.  A quick fix or scriptwrapper that could cause the neccessary
>framebuffer shifts?
>  
>
I used xdm, and got a problem like this. Whenever X
restarted on the first head, it changed the framebuffer-to-
vga-connector mapping, making both screens show the same.

Fortunately, xdm lets you run a script whenever the xserver
starts and another whenever an xserver stops.  There I put
calls to a program that mapped screens the way I wanted them,
the end result being that a xserver restart caused a short blink
on the other display.

>B.  A way to prevent the graphics card form re-initializing?
>  
>
Several ways:

1. Use the framebuffer xserver.  It is unaccelerated, but more
    than fast enough for 2D graphichs.  You'll loose accelerated
    3D though.

2. Or set things up so X doesn't restart just because someone logs
    in/out.  Then, the problem will only happen once, at boot-time.

3. FIX the stupid xserver! Make it deal with its own card only, and
    never ever touch "legacy vga adresses" which may very well belong
    to another card.  Also, in the case of X running on a single head
    belonging to a dualhead card, fix X so it doesn't mess with the
    other head AT ALL.

Helge Hafting