XDC: randr extension for full display state setup (full set of outputs and crtcs in one shot)

[Dave Airlie]

This was in ajax's summary and I just wanted to raise the issues with
this before anyone seriously started thinking about it.

1. We should not fail modesetting unless its an extreme situation, we
should endeavour to provide the remote client as much information as
it requires to pick a set of modes the gpu can actually set. It this
is just a workaround for this case then you should fix the randr
protocol to allow smarter client situations.

2. multi-seat on a single card - what happens if we give a crtc to each
user with outputs partitioned between them? what if a single X server
isn't running all the bits of the card, or has them all exposed.

I'd be interested in the situations where something like this is
actually required, i.e. I'm sure it can allow for smoother mode
setting when someone swaps connectors, but thats probably not the
common case.

Dave.