Dual Head, 8bpp and Centos 5 problem

[Alex Deucher]

On Fri, Jun 20, 2008 at 4:32 AM, Neil Thompson <abraxis at metroweb.co.za> wrote:
> Hi all,
>
> I have a legacy app which only runs in 8bpp that I have to
> get working on a CentOS 5 platform (xorg-x11-server-1.1.1 +
> Red Hat patches).  The app requires dual head, non cloned
> displays.
>
> The problem is that I cannot get X to come up in dual head
> mode when the DefaultDepth is set to 8.  Other depths (16 and
> 24) work fine, but when I change the DefaultDepth to 8, both
> screens display their built-in made change message, but only
> the primary (I assume) screen is initialised properly (the "X"
> comes up on it and I can move it around).  When I try to move
> the cursor to the other screen, it just disappears.  This is
> with the mga driver and a dual DVI card (hardware is fixed -
> I have to use it).

My rusty recollection is that 8 bpp is not possible on crtc 2 (hw limitation).

Alex