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Old 07-09-07, 05:25 AM   #1
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Join Date: Nov 2006
Posts: 95
Default Serving two users with one GPU?


I'm using a GF 7600GT with two connected monitors, amd64 smp, kernel 2.6.20, xorg 7.2, driver version 8776 (gentoo stable).

I'd like to be able to have two persons using one machine, each getting his own mouse, keyboard and monitor.
The computer is usually configured for TwinView, which works fine and everything, so there are no apparent flaws in my system or hardware.

At first I tried configuring my card without TwinView (getting :0.0 and :0.1). Configuration worked, I had two seperate screens, both running a copy of my desktop environment. Well, both screens being run under just one user account isn't perfect, but wouldn't be a huge problem either. It's just that I still had only one mouse pointer (which wasn't limited to one screen) and only one keyboard focus.
I didn't find anything on 'man xorg.conf', it's either 'send core events' or 'be completely ignored by all my applications', but I couldn't find a way to assign an input device to a specific screen.

I guess there's a '1 X server = 1 person' policy somewhere (which would be reasonable), so my second attemt was to start two instances of xorg, one screen on :0 and the other on :1.

well, after creating two ServerLayouts and everything, both worked individually, I could even start both X servers simultaneously. But only one screen was visible at a time, the other was always blank and didn't accept keyboard or mouse input. I had to switch between them using Ctrl-Alt-F7 / F8.
My xorg.conf from this attempt is attached, but I tried so many different variations that it seems pointless. Please note that I did not yet attach a second keyboard, since I currently don't have a second one, but I doubt that's the problem (or is it?).

I noticed that glxgears running on one X server will still continue drawing while switched to the second X server, so there doesn't seem to be a problem with simultanous access to the GPU.
The problem seems that each X server will use it's own Ctrl-Alt-F? slot (VT?), thus blocking input and blanking output when switched away.

Is there a way to get this working as I intended?
Would installing a second GPU help? (I doubt it, but I do have an old 6600GT around)
Or is even that useless, as linux will only allow one active X server no matter what?

thanks for reading,
Attached Files
File Type: txt xorg.conf.txt (2.3 KB, 131 views)
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