From: Sebastian Biallas <sb@biallas.net>
To: Prakash Punnoor <prakash@punnoor.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: PCI-DMA: Disabling IOMMU
Date: Wed, 18 Oct 2006 17:51:57 +0200 [thread overview]
Message-ID: <45364D9D.2060003@biallas.net> (raw)
In-Reply-To: <200610181741.03428.prakash@punnoor.de>
Prakash Punnoor wrote:
> Am Mittwoch 18 Oktober 2006 17:03 schrieben Sie:
>> Linux ouputs some strange "PCI-DMA: Disabling IOMMU" on booting. It's a
>> ALiveNF4G motherboard with an Athlon64 X2 running vanilla Linux 2.6.18.1
>> (which supports all hardware out of the box, pretty cool).
>>
>> Should I worry about this IOMMU-disabling? All other Linux/IOMMU stuff I
>> found had AGP or BIOS messages nearby, but I only get this single
>> "PCI-DMA: Disabling IOMMU" line, without any hint.
>
> Unless you have >=4GB of RAM using IOMMU makes no sense, thus it gets
> disabled.
Thanks for the answer (I thought that IOMMU is also used by VMMs like
XEN, for direct hardware access of the guest. But I might have
misunderstood this).
So maybe this message should read:
PCI-DMA: Not more than 4GiB RAM: Disabling IOMMU
so that people like me don't have to worry.
Regards,
Sebastian
next prev parent reply other threads:[~2006-10-18 15:52 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-18 15:03 PCI-DMA: Disabling IOMMU Sebastian Biallas
2006-10-18 15:41 ` Prakash Punnoor
2006-10-18 15:51 ` Sebastian Biallas [this message]
2006-10-18 21:16 ` Muli Ben-Yehuda
2006-10-18 21:15 ` Muli Ben-Yehuda
2006-10-18 21:15 ` Muli Ben-Yehuda
2006-10-18 21:48 ` Andi Kleen
2006-10-19 5:15 ` Muli Ben-Yehuda
2006-10-19 11:52 ` Andi Kleen
2006-10-19 12:08 ` Alan Cox
2006-10-19 13:04 ` Andi Kleen
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