real addresses in protected mode.

[Brian Boesch]

---------

Does anyone know how to reference absolute machine addresses
from a device driver?

This problem arrises in two variants:

	1. How do I reference a memory mapped device(like the display).

	2. How do I find the absolute address of a buffer within
		a process to allow me to do a DMA into it?

The SCO-Xenix manuals mentions routines for kernel address to physical
and back.  But not how to do I/O directly into a process address space.
They mention locking processes into memory during direct I/O so
it should be possible.

Although any explanation would be VERY helpful, any example code
would be great.  (I don't care what the code does, just how it references
memory).

Thanks in advance.

Brian Boesch
	boesch at su-shasta.stanford.edu