Re: PCI domain stuff

["H. Peter Anvin" <hpa@zytor.com>]

David S. Miller wrote:
> [ Pater, please retain the CC: list in your replies.  I scan
> linux-kernel casually at best, and I probably would have missed
> this reply of yours under normal circumstances, if you had retained
> the CC: list I would have read it via my non-lkml account and therefore
> not have missed it. ]

Unfortunately, I can't, because I never see it.  One of the very few 
disadvantages with reading LKML via a newsreader.

> On Mon, 2003-06-30 at 22:47, H. Peter Anvin wrote:
> 
>>Presumably only on architectures which use memory-mapped IO address
>>space.
> 
> On ones that don't we use the x86's existing facilities for doing
> this, ioperm() and direct I/O instructions.
> 
> These issues are platform dependant for other reasons anyways
> (endianness, barrier instructions needed, etc.)

Right.  As long as this is clear to people; I'm not sure it always is.

Perhaps a libdirectio would be useful?

> But everything the most demanding testcase in userspace needs (this
> being xfree86) needs can be done with the existing facilities.
> 
> Unlike other people, I do not see the value in having 50 ways to
> do the same thing. :-)

Agreed with that, *as long as* the implementation is sane.

	-hpa