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From: "H. Peter Anvin" <hpa@zytor.com>
To: Dave Airlie <airlied@gmail.com>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>,
	Brice Goglin <brice.goglin@gmail.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	David Airlie <airlied@linux.ie>,
	dri-devel@lists.freedesktop.org,
	Andy Lutomirski <luto@amacapital.net>
Subject: Re: MTRR use in drivers
Date: Sun, 23 Jun 2013 13:38:46 -0700	[thread overview]
Message-ID: <51C75CD6.5010206@zytor.com> (raw)
In-Reply-To: <CAPM=9tzkJTf4d=HfBUs3VwmNG1+Zo5J-JURYd4mYcJ82yXZOKg@mail.gmail.com>

On 06/23/2013 01:30 PM, Dave Airlie wrote:
>>>> Why do you care about performance when PAT is disabled?
> 
> breaking old boxes just because, is just going to get reverted when I
> get the first regression report that you broke old boxes.
> 

Not "just because", but *if* the choice is between breaking old boxes
and breaking new boxes I'll take the latter.

> Andy Lutomirski just submitted a bunch of patches to clean up the DRM
> usage of mtrrs, they are in drm-next, afaik we no longer add them on
> PAT systems.

Fantastic news.  No issue, then, and no need to break anything.

The only problem I see with having ioremap_wc() installing an MTRR on
non-PAT, rather than pushing that into the drivers which is clearly not
the right thing, is that we will need a hook to uninstall it when the
mapping is destroyed.

	-hpa




  reply	other threads:[~2013-06-23 20:39 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-21  5:00 H. Peter Anvin
2013-06-23  6:35 ` Brice Goglin
2013-06-23 14:07   ` H. Peter Anvin
2013-06-23 19:29     ` Henrique de Moraes Holschuh
2013-06-23 20:02       ` H. Peter Anvin
2013-06-23 20:30         ` Dave Airlie
2013-06-23 20:38           ` H. Peter Anvin [this message]
2013-06-23 20:54             ` Dave Airlie
2013-06-23 20:58               ` H. Peter Anvin
2013-06-23 21:27                 ` Dave Airlie
2013-06-23 23:09             ` Andy Lutomirski
2013-06-23 21:56         ` Henrique de Moraes Holschuh
2013-06-23 22:10           ` H. Peter Anvin
2013-06-24  0:02             ` Henrique de Moraes Holschuh
2013-06-24  0:31               ` H. Peter Anvin

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