[ltp] Internal/external display use

[Markus Alt]

Lately there has been some discussion on the list about the usage of external
monitors attached to ThinkPads. This covered the "intern_disp" and
"extern_disp" option resp. within the "Device" section of /etc/XF86config. Some
people asked whether it was possible to run an external monitor with a
different resolution than the internal display.

I have a similar question to which I still don't have an answer, even after
having read the above discussion several times. Maybe someone has a hint, so
here's what I want to do:

At the office, my ThinkPad (770E running SuSE 6.4) is attached to the 2nd input
of my RS/6000 workstation's monitor (IBM P260) with the same resolution as for
the internal display, 1024x768 (the 770E like many others can't do more). As
there are different horizontal sync frequencies and vertical refresh rates for
the internal and the external display, I have two /etc/XF86config.* files.
Depending on which display I intend to use, I symlink /etc/XF86config to the
appropriate file, restart the X server (via kill -HUP `pidof X`) and the KDE
login manager is displayed properly on the selected screen.

Now, as I take my ThinkPad home after work, I'd like to activate the internal
display after having worked with the external monitor in the office. But if I
send a hangup signal to the X server, my KDE session gets killed, of course.
Thus I'm forced to log out of KDE before beeing able to toggle the display
safely. And this is what I want to avoid, in order to keep my X apps running!

So here's my question: Does anybody know a way to make the X server reread its
configuration file *without* killing running X applications? Other possibility
(and that's where is the cross-link to the former discussion mentioned above):
Define the specs for two different displays within a single /etc/XF86config
file, toggle between them with any key sequence and activate the appropriate
display with Fn-F7. Can this be done and if yes, how does such a XF86config
look like?

Although I hate comparison between a real operating system and eh ... (don't
tell!), what I want to do is possible unter WinNT! Having started my ThinkPad
with the LCD activated and then switching to LCD+external with Fn-F7 shows the
evil pseudo-OS' desktop on both screen (flickering a bit on the external
because of the 60 Hz refresh rate which is limited by the max. for the LCD).
Pressing Fn-F7 again actives only the external screen and lets me choose
different settings, i.e. a higher refresh rate (e.g. 85 Hz) for it via the
Display Properties menu. The next Fn-F7 brings me back to LCD with 60 Hz. All
this without any impact on the running apps - if no segmentation violation has
occurred meanwhile, of course ... ;-)

As I really do believe in Linux and the smartness of its community, I'm quite
sure that there must be a way to solve this. So hey, you gurus on this list,
please don't tell me that there isn't! Any help, hint or tip is greatly
appreciated!

TIA,
Markus
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