Re: [PATCH v1 00/47] mtrr/x86/drivers: bury MTRR

On Fri, Mar 20, 2015 at 4:17 PM, Luis R. Rodriguez
[off-list ref] wrote:

From: "Luis R. Rodriguez" <redacted>

When a system has PAT support enabled you don't need to be
using MTRRs. Andy had added arch_phys_wc_add() long ago to
help with this but not all drivers were converted over. We
have to take care to only convert drivers where we know that
the proper ioremap_wc() API has been used. Doing this requires
a bit of work on verifying the driver split out the ioremap'd
areas -- and if not doing that ourselves. Verifying a driver
uses the same areas can be hard but with a bit of love Coccinelle
can help with that.

We're motivated to change drivers for a few reasons:

1) Take advantage of PAT when available

2) Help with the goal of eventually using _PAGE_CACHE_UC over
   _PAGE_CACHE_UC_MINUS on x86 on ioremap_nocache() (de33c442e)

Nice!

--Andy