Multiple screens.

Alex Deucher alexdeucher at
Mon Apr 4 14:05:38 PDT 2005

On Apr 4, 2005 4:53 PM, Peter Ankerstål <uchman at> wrote:
> >
> > Yes, crtc1 is driving both displays.  both the LCD and the VGA port
> > are getting the same mode, probably 1024x768 at 60hz.  If you want to run
> > the LCD at say 1024x768 at 60hz and the VGA port at say 1280x1024 at 75hz,
> > you will need to program both crtcs (crt/display controllers); one for
> > each output.  if you just want to use one crtc to drive either the vga
> > port or the lcd, there's not really an easy way to use modes beyond
> > the capabilites of the attached monitors after X is started.
> >
> If i start two x-sessions I can run one on each screen. The one i run in
> 1024x768 Is on both screens because both screens support it. And the other session
> runs 1280x1024 And is only displayed on the external screen. (1280x1024 is not
> supported by the internal screen).
> It must be a way to do this but with only one x-session.

the only way to do simultaneous 1280x1024 on the vga port and 1024x768
on the LCD is with 2 crtcs.  the chip supports that, but the driver
does not.  one thing you could try is to start X on the vga port at
1280x1024 and then use xrandr or cntl-alt-+/- to switch the mode to
1024x768 and then use the bios fn key combination to switch the
display to the vga port and the lcd port, be careful though to make
sure you are using a 1024x768 mode that your lcd can handle (probably
60Hz). YMMV...


> --
> Peter Ankerstål.

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