Re: [PATCH] x86: PAT: Documentation: update overlapping ioremap hack recommendation
From: Paul E. McKenney
Date: Fri Mar 04 2016 - 16:09:44 EST
On Fri, Mar 04, 2016 at 08:23:26PM +0100, Luis R. Rodriguez wrote:
> On Thu, Mar 03, 2016 at 01:42:33PM -0800, Paul E. McKenney wrote:
> > On Thu, Mar 03, 2016 at 01:21:48PM -0800, Luis R. Rodriguez wrote:
> > > The current documentation refers to using set_memor_wc() as a
> > > possible hole strategy when you have overlapping ioremap() regions,
> > > that's incorrect as set_memory_*() helpers can only be used on RAM,
> > > not IO memory. This fixes that, and updates the documention to
> > > *strongly* discourage overlapping ioremap() memory uses, but also
> > > documents a possible solution should there really be no other
> > > option.
> > >
> > > Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxxxx>
> >
> > Given an Acked-by or better from the guys on the TO line, I would be
> > happy to queue it.
>
> I'll need to respin as fortunately I ended up actually not needing
> to do an overlap on atyfb, and instead just let MTRR be effective
> over an entire range that included both write-combining and strong
> UC attributes. It was a bit fuzzy as this while ago, and since its
> also obscure, its more reason to document now.
>
> Will spin a v2.
Sounds good!
Thanx, Paul