Re: Matrox G550, dual head, 1680x1050

["Hans-Jürgen Koch" <hjk@linutronix.de>]

Am Freitag, 2. März 2007 00:29 schrieb Alex Deucher:
> On 3/1/07, Hans-Jürgen Koch <hjk@linutronix.de> wrote:
> > Hi,
> > 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.
> >
> > I'm booting with video=matroxfb:vesa:0x1BB, as there is no 1680x1050 vesa
> > mode. This works, both monitors show the same and complain about the
> > wrong resolution.
> >
> > Now I start my X server (xorg.conf below) and wish to get a xinerama
> > setup. Monitor 1 switches to 1680x1050 and shows a nice clean screen.
> > Monitor 2 seems to have problems, though. I guess the card still outputs
> > the 1280x1024 set up at boot time. Colours are correct, but the image is
> > heavily distorted. It looks like the X server thinks it's 1680x1050 but
> > in fact it's still 1280x1024.
> >
> > I spent some time googling, but to no avail. Now my questions:
> >
> > Is this a known limitation of matroxfb?
> > If yes, is it considered a bug? I could spend some time looking into the
> > code. Do I have any chance to get this working in a reasonable dual head
> > configuration? Any hints?
>
> IIRC, the current mga X server doesn't know how to deal with DVI
> (single or dual ports).  DVI was only supported with matrox' binary
> module.
>

Hi Alex,
thanks for your fast reply.
Currently, I've got both monitors connected with VGA cables. The card has some 
proprietary 60-pin or so connector, and I've got an adapter caple from that 
plug to 2xVGA. Both monitors show a stable picture, but only the picture on 
monitor #1 is usable. It really looks like the X server is trying to switch 
both channels to 1680x1050, but only succeeds with the first one.

Hans

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