[PATCH] Automatically determine appropriate pipe from plane info

[Jesse Barnes]

On Tuesday, September 11, 2007, Roland Scheidegger wrote:
> On 9/12/07, Jesse Barnes <jbarnes at virtuousgeek.org> wrote:
> > Rather than keeping a copy of the plane->pipe mapping code in the
> > SAREA, just figure out what the real mapping is from the
> > DSP(A|B)CNTR register at runtime.  This should be fairly safe since
> > the DRM doesn't actually modify the pipe->plane mappings, though
> > there is the possibility for app confusion if the DDX changes the
> > mappings between a vblank swap submission and completion.
>
> Wouldn't it be simpler (if you don't want that information to be in
> the sarea) to just set the mapping with a setparam ioctl rather than
> trying to be smart and needing to figure it out every vblank?

Michel clued me in as to how we could do this with a setparam ioctl in a 
forward and backward compatible way.  We can move to that if the 
register read becomes a performance issue if needed...  And fortunately 
the other parts of the mod still make sense (i.e. changing the name 
from pipe* to plane* since the data really does belong to the plane).

Jesse