[Xorg] XInput Hotplug Additions

[Jim Gettys]

> One thing that should be possible is for two servers on one VT
> to be able to use the same device, but with different settings.
> That means X needs to keep device state info and re-instate it
> when X gets it's VT switched active and it regains devices.

I presume you mean two servers on 2 different Linux virtual
terminals.

Ugh.  Do we *really* need this complexity?

Do USB devices provide ways to save/restore such settings?
Or will the system have to shadow the state and try to
keep it consistent? 

Or is an input device assigned to a particular X server
statically?  This maps well to the situation of
multi-head systems (e.g. 441, like we've (HP) started selling
in South Africa).

You are helping stoke my head-ache ;-).

> 
>  > If you detect the idea to keep as little as possible in the
>  > X server, you're right.
>  >
>  > This is analogous to the work we want to do to get display
>  > mode setting *out* of the X server.
>  >
> It seems strange to me for X not to be in charge of display-mode
> settings. Does this mean that an OS with VT switching will have
> to track display mode states for each server on one multi-VT
> console?

Well, where should the complexity lie?

Should the operating system that inflicts the complexity
have to bear the cost, or is this something X should have to
support?

> 
> > Yeah, I have to scratch my head some.  It also looks like some stuff
> > is missing (e.g. control for force feedback joysticks.
> 
> The BIG design problem here is the lack of extensibility of Controls
> and Feebacks in a way that doesn't require an X protocol changes.
> 
> Another really useful thing is an Atom to describe individual
> control items, rather than just axis 1 through n.
> 

Could be.  We have to look into this all more.  We know we
have to add to XInput for hotplug, and if there are other issues
clearly that need fixing, now is probably the time.
                           - Jim