Re: Using Dual head card with framebuffer

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

Claude Ferron wrote:

> Hello to everyone,
>
>     For quite a while now, I have been trying to get an ATI Radeon 
> 7000 Dual headed to work with XFree86 4.3.0. What I'd like to do is 
> the following:
>
> A) Put more than one card in the system (3 in fact... 2 PCI and 1 
> AGP) Have each head of the cards to work independently
> Example:    Card #1 --> head #1 = /dev/fb0, head #2 = /dev/fb1 
>                      Card #2 --> head #1 = /dev/fb2, head #2 = /dev/fb3
>                      Card #3 --> head #1 = /dev/fb4, head #2 = /dev/fb5
>
> Is this possible with radeon or NVidia Card? I know it is with Matrox 
> G400 & G450

Yes, this is possible with matrox as the matrox driver actually gives you
one framebuffer per head. Most other drivers don't they only
gives you one framebuffer per card. That limits the above scheme.

Further, most linux framebuffer drivers can't use their cards unless
the video bios initialized them first. Now, the bios usually only
initialize the first card.  There are some exceptions when you have
several cards from the same manufacturer. 
If you get this problem, the framebuffer drivers won't load.
The solution is to briefly run X on all the cards, as X can be
configured to initialize each card using int10. (for example,
one special xserver set up just for this purpose which claims
all the cards, initialize them, and then exits.)
After this, feel free to load framebuffer drivers which will now
recognise the initialized cards.

>
> B) Have multiple X server to run independently and simultaneously  on 
> each cards head (I was able to do this with 6 cards with PCI address 
> method ex: 1:0:0 but not with frame buffer on dual head)

Well, this is usually the best way, because you may have accelerated drivers
this way.

>
> So far, FrameBuffer is working on only one card, and one head... 
> really basic.

Framebuffer X is trivial to set up once you manage to load the framebuffer
drivers.  It is unaccelerated though.

>
> My questions.
>
> 1) Is this the correct place to ask this question? If not what are 
> other resources or website.

It is certainly a good place.

>
> 2) If you know how to achieve my task in section A, help me please...

See what I wrote above.

Helge Hafting