Matrox G550, dual head, 1680x1050

Hans-Jürgen Koch hjk at
Fri Mar 2 07:10:57 PST 2007

Am Freitag 02 März 2007 15:39 schrieb Tilman Sauerbeck:
> Hans-Jürgen Koch [2007-03-02 10:53]:
> > I'm the proud owner of two NEC MultiSync 2070WNX monitors (1680x1050) and
> > a Matrox G550 dual DVI card. I'm now trying to set up a dual head
> > configuration with this equipment.
> >
> > [snip]
> >
> > Is this a known limitation of matroxfb? Or a X server bug?
> AFAIK matroxfb doesn't support the G550 dual DVI card. The mga X driver
> certainly doesn't support it yet. 

Well, at the moment I'm using the VGA outputs. Current status is:

* Without X (boot, VT) I get clean 1280x1024 on both monitors. The monitors 
interpolate that to their native resolution, both show the same image.

* With a xinerama configuration, X starts without any (EE) errors. Monitor1 
shows a clean 1680x1050 image, Monitor2 a distorted image. I can move the 
mouse or windows from one monitor to the other. The reason for the distortion 
on monitor2 is most probably that the card is still configured for 1280x1024 
while the X server thinks it's 1680x1050.

* With a mergedfb configuration, X starts with this error:
(EE) MGA(0): HALLib not loaded! NOT using "Merged Framebuffer" mode.
Afterwards I have the same image on both monitors, both clean and in 

For me, this doesn't look like "not supported". Obviously, there is a (small?) 
bug that prevents the second screen from setting the mode correctly in some 
configurations (xinerama). But both monitors can definetly output a clean 
1680x1050 image using this version of xserver-xorg. 

> You could use Matrox' official drivers 
> though.

These are closed source, aren't they?


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