From: Maurice Volaski <mvolaski@aecom.yu.edu>
To: Andi Kleen <ak@suse.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: The "Out of IOMMU space" error and the "Please enable the IOMMU option" option
Date: Mon, 19 Jun 2006 16:09:02 -0400 [thread overview]
Message-ID: <a0623095ec0b8e87b768d@[129.98.90.227]> (raw)
In-Reply-To: <200606161031.16554.ak@suse.de>
With 2.6.16.20 and iommu=memaper=4,
Jun 19 15:20:31 [kernel] [ 103.697664] PCI-DMA: Disabling AGP.
Jun 19 15:20:31 [kernel] [ 103.698226] PCI-DMA: using GART IOMMU.
Jun 19 15:20:31 [kernel] [ 103.698341] PCI-DMA: Reserving 512MB of
IOMMU area in the AGP aperture
I'm not sure why it tells me it's disabling AGP, but otherwise it looks good.
>On Thursday 15 June 2006 23:17, Maurice Volaski wrote:
>> Occasionally, we get errors like these:
>>
>> Jun 9 00:56:35 [kernel] [18020.416620] PCI-DMA: Out of IOMMU space
>> for 12288 bytes at device 0000:03:01.0
>
>
>> and it looks like it might have something to do with these messages
>> (after updating and setting BIOS as below):
>>
>> Jun 15 16:38:54 [kernel] [ 0.000000] Checking aperture...
>> Jun 15 16:38:54 [kernel] [ 0.000000] CPU 0: aperture @ 0 size 256 MB
>> Jun 15 16:38:54 [kernel] [ 0.000000] No AGP bridge found
>> Jun 15 16:38:54 [kernel] [ 0.000000] Your BIOS doesn't leave a
>> aperture memory hole
>> Jun 15 16:38:54 [kernel] [ 0.000000] Please enable the IOMMU
>> option in the BIOS setup
>> Jun 15 16:38:54 [kernel] [ 0.000000] This costs you 64 MB of RAM
>> Jun 15 16:38:54 [kernel] [ 0.000000] Mapping aperture over 65536
>> KB of RAM @ 8000000
>>
>> The box is a dual Opteron 250 with an Arima HDAMA Rev. D motherboard.
>
>Not directly - the kernel will create a fallback aperture if it can't
>find one provided by the BIOS. The default is 64MB, but it can be
>enlarged with iommu=memaper=4
>
>There was also a bug that might have caused this over longer uptimes.
>If you still see it with latest 2.6.16.stable (19 or so).
>
>If it still happens with those two changes then something is likely
>leaking mappings or your have a extreme workload that needs
>a lot of mappings.
>
>
>> First, am I correct to assume that I'm not getting the 256 MB?
>
>Yes you'll get 64MB fallback likely.
>
>>
>> Second, is the the case the BIOS is lying?
>
>Probably yes.
>
>-Andi
--
Maurice Volaski, mvolaski@aecom.yu.edu
Computing Support, Rose F. Kennedy Center
Albert Einstein College of Medicine of Yeshiva University
next prev parent reply other threads:[~2006-06-19 20:08 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-06-15 21:17 Maurice Volaski
2006-06-16 8:31 ` Andi Kleen
2006-06-19 20:09 ` Maurice Volaski [this message]
2006-06-19 20:35 ` Andi Kleen
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