Re: PCI Express support for 2.4 kernel

Jeff Garzik
2003-12-16T04:53:54Z

Linus Torvalds wrote:
> On Mon, 15 Dec 2003, Jeff Garzik wrote:
>>neat. dumb question though... how portable is set_fixmap_nocache()?

> Not very. Although it should generally be trivial to port if you need it.
[...]
> On 64-bit architectures you're not likely to ever need to worry about it,
> and then you can just map the whole thing directly (and use some special
> large-page mapping for it, at that).

Yeah, good point. IA64 with its 1001 different types of mappings and
zones can go crazy, for example.

Sounds like PCI express needs a per-architecture policy for mapping the
256MB region. Some [64b] arches can direct-map the entire area. IA32
and others can go another route.

Jeff