Re: [gdm-list] Multi-seat and multi-display support design

["Yan Seiner" <yan seiner com>]

On Mon, March 9, 2009 9:19 am, Chris Tyler wrote:
>
> On Mon, 2009-03-09 at 14:06 +0800, Halton Huo wrote:
>> Hi gdm guys,
>>
>> After Ray and Brian's help, I finish the design for Multi-seat and
>> multi-display support in ConsoleKit and newGDM. Please visit the
>> following link to review it.
>> http://wiki.genunix.org/wiki/index.php/design_for_newgdm_consolekit_multiseat_multidisplay
>>
>> I've already start coding based on this design, if anything wrong or
>> something need more discussion, please feel free to write me an email.
>>
>> Thanks,
>> Halton.
>
>
> Hi Halton,
>
> This is good work. I'm looking at this from the point of view of
> multiseat Linux systems on commodity PC hardware.
>
> When working with local multiseat systems, it will be necessary to
> specify the keyboard-pointer-video card-sound device combination (let's
> say KPVS for short) for the new seat, specifying zero or more devices
> for each. There will be at least two KPVS scenarios:
>
> - static: the KPVS devices are known in advance and should always be
> configured the same way.
>
> - dynamic: extra hardware shows up, and it needs to be configured for an
> extra seat, or assigned to an existing seat (as happens in the current
> single-seat situation when you add a mouse or keyboard). The KPVS device
> groupings need to be determined on-the-fly, probably with manual
> intervention.
>
> I'm probably missing something, but I don't see how KPVS information is
> either configured into ConsoleKit or passed through ConsoleKit to the X
> servers in the design linked above.
>

I started on this but quickly abandoned it...  Too much to do and too
steep a learning curve.  :-(

My concept was to tie a USB hub to a seat.  That way, any device plugged
into that hub belonged to the seat.  There is an issue with ownership and
some security issues, but from reading the consolekit docs this could be
dealt with.

This gets around the issue of dealing with keyboards, sound devices, mice,
DVD players, mp3 players, cameras...

I'm assuming my users will be plugging in any/all of those and I would
like for them to show up in the right seat.

The other issue, which I haven't solved or even figured out how to
approach, is one of turning off the monitor when not in use.  The systems
I have use multi-output video cards, with an underlying X server and
Xephyr on top.  Xephyr doesn't do DPMS, so the monitors stay on all the
time.

--Yan

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