Date: Fri, 4 Mar 2016 20:23:26 +0100
From: "Luis R. Rodriguez" <mcgrof@kernel.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>, bp@alien8.de, mingo@kernel.org,
        tglx@linutronix.de, hpa@zytor.com, toshi.kani@hp.com,
        airlied@redhat.com, benh@kernel.crashing.org, mst@redhat.com,
        vinod.koul@intel.com, jgross@suse.com, daniel.vetter@ffwll.ch,
        luto@amacapital.net, linux-fbdev@vger.kernel.org,
        linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
        x86@kernel.org, linux-doc@vger.kernel.org, corbet@lwn.net
Subject: Re: [PATCH] x86: PAT: Documentation: update overlapping ioremap hack
 recommendation
Message-ID: <20160304192326.GU25240@wotan.suse.de>
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 <20160303214233.GN3577@linux.vnet.ibm.com>
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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@kernel.org>
> 
> 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