nvidia-glx-new and TwinView

[Clayton]

>  >     I played with nvidia-settings tool and got somehow a TwinView (dual
>  >     monitor) setup running. My main monitor is running on 640x480 and my
>  >     second monitor is running on 1280x1024. 1280x1024 should be the same
>  >     resolution on both monitors because both monitors are the same models.

Sometimes... depending on the monitor, the nvidia-settings tool
incorrectly detects one of the monitors (I haven't checked with nVidia
to see if this is a known bug).  It then defaults to what I call
"safe" settings and you end up with one of the monitors set to a max
of 640x480.  This would happen to me when one of my monitors was an
LCD TV capable of up to 1400x900 (it would be incorrectly detected and
best i could get was 640x480).

The main culprit is the Monitor0 or Monitor1 refresh settings.  If the
monitors are the same, you should see identical HorizSync and
VertRefresh values.  If the monitors are different.. there is a manual
way you can figure it out and manually tweak your xorg.conf to get it
working the way you want.

So.. if the monitors are identical, edit your xorg.conf, and copy the
correct HorizSync and VertRefresh values.  Save and restart X.

If the monitors are different....
----------
 - make an initial backup of your working xorg.conf (just in case all
goes wrong, you can set things back to the last known working
state).... eg: sudo cp /etc/X11/xorg.conf /etc/X11/xorg.conf.working

 - Run nvidia-settings and configure for twinview.  Allow it to set
the "wrong" 640x480 values for the second monitor.  Save the settings
to the xorg.conf file.

 - make a backup copy of the xorg.conf eg: sudo cp /etc/X11/xorg.conf
/etc/X11/xorg.conf.firstmonitor

 - swap the monitor cables over

 - run nvidia-settings and go through the process of setting up
Twinview again.  Note, you may need to force nvidia-settings to
re-detect the monitors.. the most reliable way I found was to copy the
last known working single monitor configuration back to xorg.conf (you
made a backup of that working configuration right?), restart X, and
then run nvidia-settings.

 - once you have two xorg.conf files, one where monitor0 is set up
correctly, and one where monitor1 is set up correctly, open the two
xorg.conf files (xorg.conf and xorg.conf.firstmonitor) and copy the
Section Monitor values over (from the xorg.conf.firstmonitor file) and
the Section Screen values (from the xorg.conf.firstmonitor file).  You
have to use a little thinking to make sure you get the Monitor0,
Monitor1, Screen0 and Screen1 values in the right places... make sure
that they match to where each monitor is physically plugged into the
video card.

 - save and restart X.

This in theory should give you a fully functioning dual monitor setup
with all the right settings - well it's what I ended up doing to get
my set up working "right".

Once you've done this, you should also be able to use nvidia-settings
to do things like change resolutions for either monitor etc.

Remember, if all goes wrong, you still have a backup of the last known
working xorg.conf file and you can recover things by simply copying it
back: sudo cp /etc/X11/xorg.conf.working /etc/X11/xorg.conf  and then
restarting X.

C.