pseudo multi-seat with dual head

[Richard Morton]

Hi,

Sorry if I have sent this to the wrong list, this is my first posting
to the list and so please do go easy on me. I looked for archives to
search but couldnt find any. Also I saw the phoronix forum; is that
the place I should be asking or these official lists?

this seems to be a related thread:
http://phoronix.com/forums/showthread.php?24646-Zaphod-w-multiseat
and http://www.phoronix.com/scan.php?page=news_item&px=NzQxMg

and http://netpatia.blogspot.com/2009/06/multiseat-in-ubuntu-904.html

but they are using Xephyr (is that the current and right way to do it?)

I am using MythTV. In case you havent come across it; MythTV seperates
TV recording daemon from the presentation of playback, called a
backend and a frontend respectively. A master backend is the backend
that also runs the MySQL instance.

I have recently moved my combined master backend/frontend from a
cupboard near the lounge downstairs to a cupboard above the lounge
upstairs, which has the added bonus of also moving the machine to
within 5 metres of both primary viewing locations. I am therefore
looking to use multi-seat linux; although I dont mind if both sessions
are actually logged in to the same user, but I would want the power
management to turn the monitors on and off independantly depending on
usage of the respective "interface".


The box is a Q6600 based system, 4gb ram with nvidia 8500gt/512MB
(dvi-d, vga, svideo outputs) and using ubuntu 10.04LTS 32bit,myth
0.23.1 and the proprietary nvidia drivers (196 series I think).

So this is my plan/desire...
Using a single graphics card (either the currently installed one or if
required; upgrade it to a new one)...
 - VGA output of graphics card and USB speakers run to bedroom
 - DVI-D output runs to lounge and digital audio output from MB runs
to AV receiver which then powers the left,centre&right speakers (no
surround sound)

both are independently to be controlled via a combination of PS3
bluetooth remotes (currenlty using the uinput module -
http://www.mythtv.org/wiki/Sony_PS3_BD_Remote#uinput_kernel_module_method)
and network control


So, my questions:
0. How should I do this, what is the preferred/supported x
configuration; or is it not possible?
1. is anyone doing this or something very similar and is there a guide
to do this that someone has used to implement this and recommends?
2. is the graphics card 8500gt up to the job - I have been using it in
dual head mode for sometime with no issues.
3. how do I segregate the bluetooth signals (for the remotes) to the
different "seats", will I need to find an alternative to uinput?
4. I am using VDPAU currently; I assume I should disable this for one
of the frontends, What would happen if I leave it on and both systems
attempt to access vdpau at the same time; will the second frontend
silently fail to get the resource and drop back to cpu decoding or a
user noticable error?
5. the same questions as 4, but with a gt430 card instead! ?
6. anticipated upgrade of linux issues?
7. anticipated upgrade of mythtv issues?

I have seen and read threads about this; but these specific questions
have never been answered or are very old. I also saw and read the
thread on dual-head / multi-frontends... but thought this was
different enough to deserve its own thread.

thanks for your time.

Richard