[ltp] Use external monitor (disable pixel stretching?)

Gregor Rojec-Goldmann linux-thinkpad@linux-thinkpad.org
Mon, 26 May 2003 21:25:38 +0200

I hava a T30 with the Radeon Mobility M6 LW (7500). XFree86 4.3 works 
fine, 4.2 has a very buggy radeon driver.

Here is my XF86Config-4 for 4.3 with a 1024x768 beamer and cloned 
xinerama (both display show the same image):
I think the beamer should be connected when starting X.

If you use 4.2, try following two config files:

Start X with beamer disconnected. Connect the beamer and press Fn F7 and 
you will get the picture on the beamer, but no picture on the notebook 

With this configuration file, I get to see a cloned image on both 
displays, but unfortunately no mouse pointer on the beamer.
Start X with beamer disconnected, connect beamer and dont touch Fn F7.

This worked for me after a lot of experimenting. The main trick with 4.2 
was to connect the second display after X was started.

Screen expanding option in bios might also be an issue. I also dont use 
framebuffer because of problems when resuming from suspend.

Good luck,

Tom Grydeland wrote:
> Hello, Thinkpaders!
> I am trying to use a TP T30 with an external projector.  I am able to
> connect a projector to the VGA out and get a picture with no trouble.
> The resolution of the thinkpad (1400 x 1050) is greater than that of the
> projector (1024 x 768) which leads to problems.  I end up seeing only a
> section of the total screen area, with the top right corner of the
> screen seen through the projector being close to (but not exactly equal
> to) the top right of the 1400 x 1050 screen, so a large section of the
> left hand side of the screen and a sizable chunk at the bottom is lost.
> In addition, some lines in the middle of the display do not appear in
> the projector image.  This picture is identical for console
> (framebuffer) and X display.
> I have tried setting a lower resolution in the X configuration, but the
> X server "stretches" the pixels to fill the whole of the screen, and I
> end up with a partially visible screen of stretched pixels -- not
> entirely satisfactory.
> I have also tried to set up a multi-head layout using separate Device
> sections (screens 0 and 1) for the Radeon device and separate Screen
> sections for the internal and external screens, but this results in the
> projector showing only a "melting" image for a few seconds before
> returning to the truncated mirrored view.  There is also an error
> message in /var/log/XFree86.1.log about
> (EE) No Screen section called "ska"
>  ...
> Fatal server error:
> no screens found
> (I am not even sure this card supports multi-head, to be honest)
> Has anyone got a T30 with 1400 x 1050 native resolution to talk to an
> external monitor or projector with lower resolution, and if so, would
> they be willing to let me know how?
> Thanks in advance,