randr provider object

[Dave Airlie]

Hi,

so as part of hotplug I've started to specify a "provider" object to
basically represent a GPU.

http://cgit.freedesktop.org/~airlied/randrproto/commit/?h=provider&id=670d2762a5c92da778fc3be4ad5a6b952e4f4027

The idea of a provider is you have multiple providers per protocol
screen, and they have a list of roles.

Current roles are:
a) master - a fully rendering and displaying GPU - initially I'd allow
only one master per screen, when the code gets to replacing xinerama
(i.e. shatter works) then we'd allow multiple masters per protocol
screen.

b) offload slave
This is a slave device that can offload DRI2 operations to. i.e. GL
and VDPAU so far. This is what the second GPU in an optimus laptop
would be.

c) output slave
This is a slave that we can offload a chunk of the screen outputting
to. It doesn't render any operations. The idea would be the primary
master GPU would provide a shared shadow pixmap with the slave, and
the primary GPU would take care of dirty updates to that pixmap, and
the slave output would just scanout. USB output devices are one use
case, the other would be for the intel GPU on optimus systems where
the nvidia is in charge of rendering the desktop, but cannot write
direct to the LVDS/eDP.

The provider object also contains the list of crtcs and outputs
controlled by this provider.

The set provider API is then used to dynamically do things, like
attach/detach output slaves, switch an offload slave into a master
(GPU switching), etc.

I'm just wondering what other info I should or shouldn't be including
in the provider, I sort of think some sort of device identifier or bus
id would be useful, maybe the input guys have some stuff they found
useful to know. Like we'd probably need a way for GUI tools to display
info about the provider like a name or something.

Dave.