Multi-screen setup (:0.0 :0.1 etc.), how?

[Nils Faerber]

Hello!
For quite some time now I am trying to properly setup a multi-screen
setup which used to work fine with older X.org versions (I do not
remember when it started to fail).

What I want is *not* one big sized desktop across all attached monitors
(which used to be called xinerama IIRC). What I want is properly
configured separate screens of one X11 display, i.e. I want displays
:0.0, :0.1, :0.2 etc. for each monitor. (I should probably add that the
monitors are attached to the same card, in my case a Thinkpad with one
internal + one external monitor).

I have three reasons for this.
One is that I have different monitors attached - one is the laptop's
built-in 15" UXGA (1600x1200) and the second is an external 17" 16:9
1680x1050 screen. They have different DPIs and with the current model
the DPIs do not match any more since I get one big screen with a virtual
size of 3280x1200 and the same DPI on both screens (which is in my case
wrong). So fonts get different sizes on each screen which is ugly.
Second is that sometimes applications are not usable. The second monitor
has a lower Y resolution but the virtual resolution is 1200. What
happens then is that applications miscalculate the vertical bottom of
the screen and e.g. context menus show entries below the screen's end
which makes them unusable - nasty.
And finally for usability reasons - but this is personal. I like to have
my communication applications on the second screen always visible (like
email, jabber, etc.). The second screen should not be affected by
switching virtual desktops on my other work-screen. Well, you can stick
them to the desktop so they show up on all virtual workspaces but hey -
when it worked (before some x.org version I forgot) I had 2 x 6 virtual
workspaces which worked separately and I loved it - now I only have 1 x
6 big virtual workspaces.

I am searching for the proper solution for months now - in non regular
intervals. I have found no clue about it in the x.org documentation, in
the FAQs or by intense googling. If this could be achieved with xrandr I
would be extremely happy! If I need to tweek xorg.conf - fine with me.
But I tried a lot of xorg set-ups that are suggested on various
locations but all set-ups either turned ut not to change anything, i.e.
I end up with the big virtual screen, or just one screen (the main),
cloned output (even worse since useless for me) or not working at all.
But none gave me back my multiple displays setup :(

I am desperate...
So if anyone could help me with this I would be extremely happy! I would
even volunteer to document it somewhere (x.org wiki?).

Thanks in advance!

Cheers
  nils

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