[linux-audio-dev] Two or more monitors) Re: Project: modularsynth editor

[David Olofson]

On Monday 19 January 2004 18.11, Steve Harris wrote:
> On Mon, Jan 19, 2004 at 04:41:06PM +0100, Martijn Sipkema wrote:
> > [...]
> >
> > > Xinerama _does_ support open GL, at least with my matrox card,
> > > I can have openGL on one monitor of the two. That is a
> > > limitation of the card hardware, AFAIK, not of X.
> >
> > I doubt this is a hardware limitation. The hardware just renders
> > to AGP or local memory. I may be wrong though...
>
> IIRC Matrox cards have a way of making a single framebuffer (with
> xinerama hints) that appears on two monitors. That way you should
> get 3d accel on both displays.

ATI has something similar, but their drivers don't seem to work with 
Xinerama the normal way. It (sort of) works though, and as long as I 
don't try to throw extra cards in the mix, I can have two independent 
desktops (separate buffers, separate pixel formats etc) and still run 
OpenGL on both.

There is another mode, where a single buffer forms a big desktop, of 
which each RAMDAC displays a part. Seems like stupid driver 
limitations restrict this mode to using the same resolution for both 
heads, but I'm not sure. (Don't care about a few % wasted VRAM - the 
screens aren't that different in size.) However, ATI had me believe 
you can't run 2048x1536 on the analog output while using the DVI 
output *at all* - but that's obviously not the case, as I'm doing it 
right now...


//David Olofson - Programmer, Composer, Open Source Advocate

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