[PATCH] drm/gem: add functions to get/put pages

[Alan Cox]

> Well I think for this case the solution is simple: Tiling not allowed
> if userspace is too dumb to properly round the buffer up so it
> fulfills whatever odd requirement the hw has. I think hiding the fact
> that certain buffers need more backing storage than a naive userspace
> might assume is ripe for ugly problems down the road.

That depends a lot upon the interface. One good reason for hiding it for
example is that if you have hardware where a limit goes away (or worse
yet appears) in some rev of the device or an erratum you don't have to
issue a new X server.

For some of the other interfaces like the dumb fb api it's even more
important the code doesn't know.

I don't however think the helper should know about padding because I
think a driver can implement its own function which wraps the helper and
then adds the padding itself ?

Alan