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

David Olofson david at olofson.net
Tue Jan 20 03:45:58 UTC 2004


On Tuesday 20 January 2004 00.29, Martijn Sipkema wrote:
> [...]
>
> > > 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.
>
> Most (all?) hardware will support this (and all should).

Yes. Not being able to render into a certain part of VRAM seems like a 
rather strange limitation...


> > 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.
>
> It is to be expected that a single rendering context has only one
> framebuffer configuration. "Consumer" hardware does not have a per
> pixel framebuffer configuration stored in the framebuffer together
> with the color (and possibly clipping) data; a rendering operation
> expects a single config.

Right, but resolution is just a matter of RAMDAC parameters. All I 
want is a 3856x1536 framebuffer with one RAMDAC displaying a 
2048x1536 window and the other displaying a 1808x1356 window. I don't 
care about one tiny MB of VRAM being invisible.

BTW, the 8800 is limited to 2048x2048 for OpenGL contexts, but that 
seems to be per context, and I'm not inderested in stretching a 
single context over both screens anyway. (I'm not interested in 
stretching *anything* over both screens; just moving windows across 
them, which is not possible with independent desktops.)


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

.- Audiality -----------------------------------------------.
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