xrandr not happy about external monitor

[Alex Deucher]

On Jan 28, 2008 4:51 AM, Michele Mattioni <mattions at gmail.com> wrote:
> On Jan 28, 2008 6:17 AM, Alex Deucher <alexdeucher at gmail.com> wrote:
> >
> > On Jan 27, 2008 8:08 PM, Michele Mattioni <mattions at gmail.com> wrote:
> > > Hello list,
> > >
> > > I have a laptop with a Mobility 9000 radeon and an external monitor
> > > form Acer 22inches.
> > >
> > > I'm using an ubuntu gutsy and the version of the xserver-xorg-video-ati is
> > > 1:6.7.195-1ubuntu2
> > >
> > > xrandr detect correctly the monitor:
> > >
> > > [mattions at the-tux:~]$ xrandr -q
> > > Screen 0: minimum 320 x 200, current 1680 x 1050, maximum 1680 x 1200
> > > VGA-0 connected 1680x1050+0+0 (normal left inverted right) 474mm x 296mm
> > >   1680x1050      60.0*+   60.0
> > >   1600x1200      59.9
> > >   1280x1024      75.0     59.9
> > >   1440x900       75.0     59.9
> > >   1280x960       59.9
> > >   1280x720       59.9
> > >   1024x768       75.1     70.1     60.0
> > >   832x624        74.6     74.8
> > >   800x600        72.2     75.0     60.3     56.2
> > >   640x480        75.0     72.8     66.7     60.0
> > >   720x400        70.1
> > > LVDS connected 1400x1050+0+0 (normal left inverted right) 0mm x 0mm
> > >   1400x1050      61.8*+
> > >   1280x800       60.0
> > >   1280x768       60.0
> > >   1024x768       60.0
> > >   800x600        60.3
> > >   640x480        59.9
> > > S-video disconnected (normal left inverted right)
> > >
> > > However I can't see any image on the screen.
> > > The screen is somehow blue, and if I give the instruction like
> > > [mattions at the-tux:~]$ xrandr --output VGA-0 --off
> > >
> > > the screen turns black.
> > > So I guess it's responding.
> > >
> > > My Xorg log is here:
> > > http://www.ebi.ac.uk/~mattioni/log/Xorg.0.log
> > > Do you have any idea?
> >
> > This sounds like a sync polarity issue.  Do any other modes on your
> > monitor work?  According to your log, you have two 1680x1050 modes
> > with different polarities:
> > >   1680x1050      60.0*+   60.0
> > (II) RADEON(0): Modeline "1680x1050"x60.0  146.25  1680 1784 1960 2240
> >  1050 1053 1059 1089 +hsync -vsync (65.3 kHz)
> > (II) RADEON(0): Modeline "1680x1050"x60.0  146.25  1680 1784 1960 2240
> >  1050 1053 1059 1089 -hsync +vsync (65.3 kHz)
> > see if switching to the other one makes the monitor work (use xrandr
> > --verbose to look up the mode ids).
> >
> > Alex
> >
>
> Thanks Alex for the quick answer,
> can you tell me how I can switch the polarities?
>

The following should work:

xrandr --newmode "1680x1050_60.00"  146.25  1680 1784 1960 2240  1050
1053 1059 1089 -hsync +vsync
xrandr --addmode VGA-0 "1680x1050_60.00"
xrandr --output VGA-0 --mode "1680x1050_60.00"

Alex