[PATCH] x86: enable DMAR by default

[PATCH] x86: enable DMAR by default

[Kyle McMartin]

From: Kyle McMartin <kyle@redhat.com>

Now that the obvious bugs have been worked out, specifically
the iwlagn issue, and the write buffer errata, DMAR should be safe
to turn back on by default. (We've had it on since those patches were
first written a few weeks ago, without any noticeable bug reports
(most have been due to the dma-api debug patchset.))

Signed-off-by: Kyle McMartin <kyle@redhat.com>

---
Probably 2.6.29 material, but should definitely go in for 2.6.30.

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 9c39095..bc2fbad 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1803,7 +1803,7 @@ config DMAR
 	  remapping devices.
 
 config DMAR_DEFAULT_ON
-	def_bool n
+	def_bool y
 	prompt "Enable DMA Remapping Devices by default"
 	depends on DMAR
 	help

Re: [PATCH] x86: enable DMAR by default

[Ingo Molnar]

* Kyle McMartin <kyle@infradead.org> wrote:

> From: Kyle McMartin <kyle@redhat.com>
> 
> Now that the obvious bugs have been worked out, specifically 
> the iwlagn issue, and the write buffer errata, DMAR should be 
> safe to turn back on by default. (We've had it on since those 
> patches were first written a few weeks ago, without any 
> noticeable bug reports (most have been due to the dma-api 
> debug patchset.))
> 
> Signed-off-by: Kyle McMartin <kyle@redhat.com>
> 
> ---
> Probably 2.6.29 material, but should definitely go in for 2.6.30.

Definitely agreed on .30. Can do it in .29 as well if David and 
the rest of the Cc: agrees.

	Ingo

Re: [PATCH] x86: enable DMAR by default

[David Woodhouse]

On Thu, 2009-02-26 at 19:03 +0100, Ingo Molnar wrote:
> * Kyle McMartin <kyle@infradead.org> wrote:
> 
> > From: Kyle McMartin <kyle@redhat.com>
> > 
> > Now that the obvious bugs have been worked out, specifically 
> > the iwlagn issue, and the write buffer errata, DMAR should be 
> > safe to turn back on by default. (We've had it on since those 
> > patches were first written a few weeks ago, without any 
> > noticeable bug reports (most have been due to the dma-api 
> > debug patchset.))
> > 
> > Signed-off-by: Kyle McMartin <kyle@redhat.com>
> > 
> > ---
> > Probably 2.6.29 material, but should definitely go in for 2.6.30.
> 
> Definitely agreed on .30. Can do it in .29 as well if David and 
> the rest of the Cc: agrees.

Definitely. I wasn't any happier than you were with the patch which
disabled it in the first place.... but it was necessary at the time.

Enthusiastically-Acked-by: David Woodhouse <David.Woodhouse@intel.com>

-- 
David Woodhouse                            Open Source Technology Centre
David.Woodhouse@intel.com                              Intel Corporation