Re: [Linux-fbdev-devel] Matrox G550, dual head, 1680x1050

[Alex D. <ale...@gm...>]

On 3/1/07, Hans-J=FCrgen Koch <hj...@li...> wrote:
> Am Freitag, 2. M=E4rz 2007 00:29 schrieb Alex Deucher:
> > On 3/1/07, Hans-J=FCrgen Koch <hj...@li...> 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=3Dmatroxfb:vesa:0x1BB, as there is no 1680x105=
0 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 outp=
uts
> > > 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 b=
ut
> > > 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 h=
ead
> > > 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 th=
at
> 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 swit=
ch
> both channels to 1680x1050, but only succeeds with the first one.
>

you should probably ask on the xorg mailing list :)
Dualhead is a bit flakey in the xorg driver at the moment, although
work is being done to fix that.  IIRC, the ordering is wrong when
programming one of the PLLs.

Alex

> Hans
>