Re: [PATCH] x86: PAT: Documentation: update overlapping ioremap hack recommendation

[Luis R. Rodriguez]

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.

  Luis