Miscellaneous ioplug questions

[Rob Duncan <rduncan@tesla.com>]

I have some questions about some ioplug implementation details:

- Is the value returned from the pointer callback supposed to be a
  monotonically increasing value, or should it wrap at the buffer size?
  The documentation says "get the current DMA position" which isn't
  clear to me.

- Must the pointer callback return values that are an integral multiple
  of the period size, or can it report partial periods?

- Should the poll FD be made writeable as soon as data is available, or
  only when at least avail_min is available?

Thanks,

Rob.