Re: Improved DRM support for cant_use_aperture platforms

[David Mosberger]

  Michel> There are a couple more, like pte_offset_kernel(),
  Michel> pte_pfn(), pfn_to_page() and
  Michel> flush_tlb_kernel_range(). Getting this working with 2.4
  Michel> seems like a lot of work and/or ugly. :\

Just goes to show how quickly one gets used to 2.5... ;-)

Let me take a look at these.

  >> (apart from PAGE_AGP, which is taken care of by the latest
  >> patch).

  Michel> Not quite, PAGE_KERNEL_NOCACHE isn't defined on all
  Michel> architectures either.

OK, I believe the only other architecture that sets
"cant_use_aperture" is Alpha.  I asked some Alpha folks several months
ago about my patch, but never got a conclusive answer.  IIRC, on Alpha
the physical address itself determines cacheablity.  If so, we can use
PAGE_KERNEL (which is universal) instead of PAGE_KERNEL_NOCACHE.

Clearly the patch needs to be tested on Alpha.  The upside is that it
should let the Alpha folks get rid of a lot of ugliness in the
ioremap() code.

	--david