R SIG Debian - Dec 2009 - [OT] What file can I use to change Ubuntu 9.10 display characteristics?

This question is vaguely related to R in that I have managed to wedge
the netbook computer that I use for demonstrations of R and I would
like to know how to un-wedge it so I can continue to give lectures
about R.

I have an ASUS eee PC running the netbook-remix version of Ubuntu
9.10.  The X server in 9.10 is a little different from earlier
versions in that it does not require an explicit configuration file
for the X server ( /etc/X11/xorg.conf, IIRC) as it can autoconfigure.
That it did fine.

When I attached the netbook to the VGA input for the video projector
in a lecture hall I found that it dropped the resolution to 640 x 480,
which is undesirably coarse.  I decided to tinker and see if I could
get it to 800 x 600 on both the built-in display and the video
projector.  I used the GUI application accessed through the menu
sequence System -> Preferences -> Display.

I believe that at one point I actually got things working that way
but, of course, I couldn't leave well-enough alone and decided to try
to get a resolution with 768 lines as I knew the projector supported
that.  That was when it all went south.  The system froze with a blank
screen and blank projector output.  I needed to do a hard power-down
and reboot without the projector plugged in.  Fortunately I didn't
lose the disk (I run ext2 file systems as a journaled file system puts
too much wear on the solid-state disk) and I can use the computer
without an external display.

Now I can use the netbook when it is not connected to an external VGA
display but as soon as I connect the external VGA it freezes,
presumably because it is trying to use an unsupported video mode.  The
information on the video modes I selected must be stored somewhere but
I can't find out where.  Does anyone know where that GUI application
caches its information?  All this GUI configuration is great unless
the thing you are trying to configure is the display and you can't get
that working.  In the old days when you needed to edit a text-based
configuration file you had a fighting chance of doing that even if you
could only get the barest of systems, a text console device, running.

Doug,

It appears (I have not upgraded my machines to 9.10 yet so I cannot 
confirm) that you can generate xorg.conf with "Xorg -configure" and
then
copy that file over to /etc/X11.  This link has some information:

http://ubuntuforums.org/showthread.php?t=1221226

Michael

Douglas Bates wrote:
> This question is vaguely related to R in that I have managed to wedge
> the netbook computer that I use for demonstrations of R and I would
> like to know how to un-wedge it so I can continue to give lectures
> about R.
> 
> I have an ASUS eee PC running the netbook-remix version of Ubuntu
> 9.10.  The X server in 9.10 is a little different from earlier
> versions in that it does not require an explicit configuration file
> for the X server ( /etc/X11/xorg.conf, IIRC) as it can autoconfigure.
> That it did fine.
> 
> When I attached the netbook to the VGA input for the video projector
> in a lecture hall I found that it dropped the resolution to 640 x 480,
> which is undesirably coarse.  I decided to tinker and see if I could
> get it to 800 x 600 on both the built-in display and the video
> projector.  I used the GUI application accessed through the menu
> sequence System -> Preferences -> Display.
> 
> I believe that at one point I actually got things working that way
> but, of course, I couldn't leave well-enough alone and decided to try
> to get a resolution with 768 lines as I knew the projector supported
> that.  That was when it all went south.  The system froze with a blank
> screen and blank projector output.  I needed to do a hard power-down
> and reboot without the projector plugged in.  Fortunately I didn't
> lose the disk (I run ext2 file systems as a journaled file system puts
> too much wear on the solid-state disk) and I can use the computer
> without an external display.
> 
> Now I can use the netbook when it is not connected to an external VGA
> display but as soon as I connect the external VGA it freezes,
> presumably because it is trying to use an unsupported video mode.  The
> information on the video modes I selected must be stored somewhere but
> I can't find out where.  Does anyone know where that GUI application
> caches its information?  All this GUI configuration is great unless
> the thing you are trying to configure is the display and you can't get
> that working.  In the old days when you needed to edit a text-based
> configuration file you had a fighting chance of doing that even if you
> could only get the barest of systems, a text console device, running.
> 
> _______________________________________________
> R-SIG-Debian mailing list
> R-SIG-Debian at r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-debian
-- 
Dr. Michael A. Rutter
School of Science
Penn State Erie, The Behrend College
Station Road
Erie, PA 16563
http://math.bd.psu.edu/faculty/rutter

On 4 December 2009 at 13:24, Douglas Bates wrote:
| This question is vaguely related to R in that I have managed to wedge
| the netbook computer that I use for demonstrations of R and I would
| like to know how to un-wedge it so I can continue to give lectures
| about R.
| 
| I have an ASUS eee PC running the netbook-remix version of Ubuntu
| 9.10.  The X server in 9.10 is a little different from earlier
| versions in that it does not require an explicit configuration file
| for the X server ( /etc/X11/xorg.conf, IIRC) as it can autoconfigure.
| That it did fine.
| 
| When I attached the netbook to the VGA input for the video projector
| in a lecture hall I found that it dropped the resolution to 640 x 480,
| which is undesirably coarse.  I decided to tinker and see if I could
| get it to 800 x 600 on both the built-in display and the video
| projector.  I used the GUI application accessed through the menu
| sequence System -> Preferences -> Display.
| 
| I believe that at one point I actually got things working that way
| but, of course, I couldn't leave well-enough alone and decided to try
| to get a resolution with 768 lines as I knew the projector supported
| that.  That was when it all went south.  The system froze with a blank
| screen and blank projector output.  I needed to do a hard power-down
| and reboot without the projector plugged in.  Fortunately I didn't
| lose the disk (I run ext2 file systems as a journaled file system puts
| too much wear on the solid-state disk) and I can use the computer
| without an external display.
| 
| Now I can use the netbook when it is not connected to an external VGA
| display but as soon as I connect the external VGA it freezes,
| presumably because it is trying to use an unsupported video mode.  The
| information on the video modes I selected must be stored somewhere but
| I can't find out where.  Does anyone know where that GUI application
| caches its information?  All this GUI configuration is great unless
| the thing you are trying to configure is the display and you can't get
| that working.  In the old days when you needed to edit a text-based
| configuration file you had a fighting chance of doing that even if you
| could only get the barest of systems, a text console device, running.

Try the 'randr' frontends.  I have used both xrandr (from a package of
the
same name) and the KRandR frontend in KDE on both my older laptop (where I
learned about xrandr during UseR :) and my netbook which has a nice but
non-standard 'hd' resolution of 1366 x 768. The last time I connected it
to a
projector I think I simply selected a lower (and more standard) resolution
from the KRandR applet in the panel.  Oh, and that was with a pre-release of
Ubuntu 9.10.  Gnome appears to have packages 'gnome-randr-applet' and
'grandr'.

And as I understand it, there is no configuration.  X11 now does everything
dynamically.  But I could be wrong.  In fact, that is quite likely as I
hardware and I usually try our best to ignore each other ...

Dirk

-- 
Three out of two people have difficulties with fractions.