Occasional dual head

[Richard Hector <richard@walnut.gen.nz>]

Hi all,

I've got an HP Compaq 6710b (intel GM965), which has been working fine.

What I want to do now is be able to use either an external screen or a
projector with it.

I've been playing with xrandr, and reading `man xorg.conf`, and reading
http://www.intellinuxgraphics.org/dualhead.html.

I now have two different displays, at their correct resolutions, which
is a good start.

What I haven't been able to figure out yet is why, when the external
monitor is active, that's where my login window goes, and that's where
my gnome panels go. I really want them to stay on the laptop display.
It's not so important for sitting at home, although it would be nice to
have those things in front of me rather than off to the side, but if I
was using a projector, it would be much better if I only displayed to
the audience what I actually wanted to.

I'm also a little confused as to how Devices, Monitors, Screens and
Displays relate to each other, as well as what I actually have in the
way of hardware.

xrandr seems to claim I have 3 outputs: LVDS, VGA and TV.
lspci says I have 2 devices:
00:02.0 VGA compatible controller: Intel Corporation Mobile GM965/GL960
Integrated Graphics Controller (rev 0c)
00:02.1 Display controller: Intel Corporation Mobile GM965/GL960
Integrated Graphics Controller (rev 0c)

I'm not sure how the 3 xrandr outputs are distributed over those 2
devices.

So far, the way I've got it configured seems to suggest I have one
Device (BusID "PCI:0:2:0" - the first of what lspci shows), with one
screen (with a Virtual size wide enough for both monitors), that
consists of 2 monitors.

There is a Screen option in the Device section, which takes an integer
(suggesting it doesn't relate to the Screen section), which looks like
I could specify which is the primary Screen - but if I only have one
Device, that doesn't help. Or should I add another Device section with
the second PCI id? Does the hardware get automagically reconfigured to
appear as 2 devices instead of one?

If someone could help clear up some of my confusion, that would be
great - and I might be able to ask some more sensible questions :-)

Thanks,

Richard