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From: "H. Peter Anvin" <hpa@zytor.com>
To: David Rientjes <rientjes@google.com>
Cc: Clemens Ladisch <clemens@ladisch.de>,
	Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [patch v2] x86: allow ZONE_DMA to be configurable
Date: Wed, 20 Apr 2011 21:07:59 -0700	[thread overview]
Message-ID: <4DAFAD9F.4020809@zytor.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1104201929170.15661@chino.kir.corp.google.com>

On 04/20/2011 07:31 PM, David Rientjes wrote:
>>
>> This isn't really a very good edit, as ZONE_DMA isn't inherently limited
>> to ISA/LPC devices (and LPC devices which do LPC-native bus mastering
>> DMA are not affected.)  ZONE_DMA is used even for some PCI devices which
>> have restrictions on the DMA address mask.
>>
> 
> Peter, do you think we can merge this patch now?  The discussion from 
> October resulted in the decision to rename CONFIG_EMBEDDED to 
> CONFIG_EXPERT and make CONFIG_GENERIC_ISA_DMA and CONFIG_ISA_DMA_API 
> configurable for x86.  That's all been done via the -mm tree and is in the 
> latest git.
> 
> We've run without ZONE_DMA for a few years without issues (and, obviously, 
> this patch) on x86.

Please address the documentation issues.  ZONE_DMA is *NOT* just for
"old ISA devices" -- there are plenty of other devices with restricted
DMA masks.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.


  reply	other threads:[~2011-04-21  4:08 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-14 18:38 [patch v2] x86: allow ZONE_DMA to be configurable David Rientjes
2011-04-15 11:42 ` Clemens Ladisch
2011-04-15 20:08   ` H. Peter Anvin
2011-04-21  2:31     ` David Rientjes
2011-04-21  4:07       ` H. Peter Anvin [this message]
2011-04-27 23:37         ` [patch v3] " David Rientjes
2011-05-04  0:00           ` David Rientjes
2011-05-04  0:20             ` H. Peter Anvin
2011-05-16 20:54           ` [patch v4] " David Rientjes
2011-05-16 20:56             ` H. Peter Anvin
2011-05-16 23:13             ` [tip:x86/mm] x86, mm: Allow " tip-bot for David Rientjes
2011-08-17 10:37               ` Borislav Petkov

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