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From: Dan Williams <dan.j.williams@intel.com>
To: "Woodhouse, David" <david.woodhouse@intel.com>
Cc: Chris Li <lkml@chrisli.org>, linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: BUG in drivers/dma/ioat/dma_v2.c:314
Date: Wed, 30 Jun 2010 12:40:28 -0700	[thread overview]
Message-ID: <4C2B9DAC.1030806@intel.com> (raw)
In-Reply-To: <1277923422.16256.8.camel@localhost>

On 6/30/2010 11:43 AM, Woodhouse, David wrote:
> On Wed, 2010-06-30 at 19:26 +0100, Chris Li wrote:
>>
>> The delta seems to be this line:
>> ioatdma 0000:00:0f.0: ioat2_set_chainaddr: chainaddr: ffffe000
>
> That's a reasonable address if the IOMMU is enabled. We start at 4GiB
> and work down, so that's the second page given out (or the first 8KiB
> chunk).
>
> It looks like the DMA is going AWOL causing the initialisation to
> fail... but it's interesting that there are no DMA faults reported by
> the IOMMU.
>

It seems the 5400 has a dedicated remapping engine just for the DMA 
device [1], is Linux only setting up the iommus per root port (which the 
DMA bypasses)??

 From the dmesg:
> IOMMU 0: reg_base_addr fe710000 ver 1:0 cap 900000c2f0462 ecap e01
> DMAR: DRHD base: 0x000000fe714000 flags: 0x0
> IOMMU 1: reg_base_addr fe714000 ver 1:0 cap 900000c2f0462 ecap e01
> DMAR: DRHD base: 0x000000fe719000 flags: 0x0
> IOMMU 2: reg_base_addr fe719000 ver 1:0 cap 900000c2f0462 ecap e01
> DMAR: DRHD base: 0x000000fe718000 flags: 0x1
> IOMMU 3: reg_base_addr fe718000 ver 1:0 cap 900000c2f0462 ecap e01

Where we expect bit 54 to be set for the DMA iommu, and it does not 
appear to show up.

--
Dan

[1]: http://www.intel.com/Assets/PDF/datasheet/318610.pdf (Section 
3.11.2 page 256)

  reply	other threads:[~2010-06-30 19:40 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-06-28 23:50 BUG in drivers/dma/ioat/dma_v2.c:314 Chris Li
2010-06-29  0:45 ` Dan Williams
2010-06-29  7:17   ` Chris Li
2010-06-29 23:20   ` Chris Li
2010-06-29 23:57     ` Dan Williams
2010-06-30  1:07       ` Chris Li
2010-06-30  4:17         ` Dan Williams
2010-06-30 18:26           ` Chris Li
2010-06-30 18:43             ` Chris Li
2010-06-30 18:43             ` David Woodhouse
2010-06-30 19:40               ` Dan Williams [this message]
2010-06-30 20:02                 ` David Woodhouse
2010-06-30 21:44                   ` Dan Williams
2010-06-30 21:59                     ` Chris Li
2010-06-30 22:04                       ` Dan Williams
2010-07-01  6:21                     ` David Woodhouse
2010-07-01  6:51                       ` Dan Williams
2010-07-01  7:12                         ` David Woodhouse
2010-07-01  7:26                           ` Dan Williams
2010-07-01  8:15                             ` David Woodhouse
2010-07-01 17:20                               ` Dan Williams
2010-07-01 17:58                                 ` Chris Li
2010-07-02 19:00                                   ` Chris Li
2010-07-05 10:16                                     ` David Woodhouse
2010-07-06 23:40                                       ` Chris Li
2010-07-07  0:51                                         ` Dan Williams
2010-07-07  0:51                                           ` Chris Li
2010-07-07  0:58                                             ` Dan Williams
2010-07-07  1:03                                               ` Chris Li
2010-07-07  3:22                                                 ` David Woodhouse
2010-07-07  3:40                                           ` David Woodhouse
2010-07-07 17:47                                             ` Dan Williams
2010-07-07 18:07                                               ` David Woodhouse
2010-07-07 21:56                                               ` Chris Li
2010-07-09 21:28                                                 ` Dan Williams
2010-07-09 22:00                                                   ` Chris Li
2010-07-10  0:09                                                   ` David Woodhouse
2010-07-15  5:41                                                     ` Dan Williams
2010-07-16 21:29                                                       ` Chris Li
2010-07-16 22:12                                                       ` David Woodhouse
2010-07-16 22:40                                                         ` Chris Li
2010-07-22  1:15                                                           ` Dan Williams
2010-07-22 21:39                                                             ` Chris Li
2010-07-22 22:00                                                               ` Dan Williams

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