xrandr weirdness: cannot find crtc

[Gilad Arnold]

Thanks, Alex.

On Wed, Jun 17, 2009 at 12:22:59PM +1000, Alex Deucher wrote:
> On Wed, Jun 17, 2009 at 3:28 AM, Gilad Arnold<arnold at cs.berkeley.edu> wrote:
> > $ xrandr
> > Screen 0: minimum 320 x 200, current 1400 x 1050, maximum 1920 x 1200
> > VGA-0 connected 1400x1050+0+0 (normal left inverted right x axis y axis) 546mm x 352mm
> >   1920x1200      60.0 +   60.0
> >   1600x1200      75.0     70.0     65.0     60.0     60.0
> >   1680x1050      60.0
> >   1600x1000      60.0
> >   1400x1050      74.8     60.0*
> >   1280x1024      85.0     75.0     60.0
> >   1280x960       85.0     60.0     60.0
> >   1152x864       75.0
> >   1024x768       85.0     75.1     75.0     70.1     60.0
> >   832x624        74.6
> >   800x600        85.1     72.2     75.0     60.3     56.2
> >   640x480        85.0     75.0     72.8     75.0     60.0     59.9
> >   720x400        85.0     70.1
> >   640x400        85.1
> >   640x350        85.1
> > DVI-0 connected 1400x1050+0+0 (normal left inverted right x axis y axis) 546mm x 352mm
> >   1920x1200      60.0 +
> >   1600x1200      60.0     60.0
> >   1680x1050      60.0
> >   1600x1000      60.0
> >   1400x1050      74.8     60.0*
> >   1280x1024      85.0     75.0     60.0
> >   1280x960       85.0     60.0     60.0
> >   1152x864       75.0
> >   1024x768       85.0     75.1     75.0     70.1     60.0
> >   832x624        74.6
> >   800x600        85.1     72.2     75.0     60.3     56.2
> >   640x480        85.0     75.0     72.8     75.0     60.0     59.9
> >   720x400        85.0     70.1
> >   640x400        85.1
> >   640x350        85.1
> > LVDS connected 1400x1050+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
> >   1400x1050      50.0*+
> >   1280x1024      59.9     60.0
> >   1280x960       60.0     59.9
> >   1280x854       59.9
> >   1280x800       59.8
> >   1280x720       59.9
> >   1152x768       59.8
> >   1024x768       60.0     59.9
> >   800x600        60.3     59.9     56.2
> >   640x480        59.9     59.4
> > S-video disconnected (normal left inverted right x axis y axis)
> 
> When the one crtc drives several monitors the mode timing must be the
> identical on both. I suspect the mode timings aren't quite the same
> across monitors for the modes you are trying to set.

Looks like at least the mode I tested with explicitly, 1680x1050, has
the same timing rates (60.0). I believe (not tested right now, not in
front of the external monitor) that I can actually activate both VGA-0
and DVI-0 at any mode (on the same rate) if I turn one off, set the
other to the desired mode, then set the first one to the same mode.
I can test if you like.

> Alternatively, xrandr isn't being smart about how it sets the mode
> which results in the error.

If this is the case, where should I report this?

Thanks.

Gilad