Re: Ricoh DMAR bug returns? (WAS Re: [PATCH v4] Quirk for buggy dmasource tags with Intel IOMMU.)

From: Pat Erley
Date: Wed May 15 2013 - 00:49:50 EST

On 04/05/2013 01:50 AM, Pat Erley wrote:
On 04/05/2013 12:44 AM, Andrew Cooks wrote:
On Tue, Apr 2, 2013 at 11:47 PM, Pat Erley <pat-lkml@xxxxxxxxx> wrote:
On 04/02/2013 10:50 AM, Andrew Cooks wrote:

On 2 Apr 2013 15:37, "Pat Erley" <pat-lkml@xxxxxxxxx
<mailto:pat-lkml@xxxxxxxxx>> wrote:
>
> On 03/07/2013 09:35 PM, Andrew Cooks wrote:
>>
>> --- a/drivers/pci/quirks.c
>> +++ b/drivers/pci/quirks.c
>>
>> +/* Table of multiple (ghost) source functions. This is similar
to the
>> + * translated sources above, but with the following differences:
>> + * 1. the device may use multiple functions as DMA sources,
>> + * 2. these functions cannot be assumed to be actual devices,
they're simply
>> + * incorrect DMA tags.
>> + * 3. the specific ghost function for a request can not always be
predicted.
>> + * For example, the actual device could be xx:yy.1 and it
could use
>> + * both 0 and 1 for different requests, with no obvious way to
tell
when
>> + * DMA will be tagged as comming from xx.yy.0 and and when it
will
be tagged
>> + * as comming from xx.yy.1.
>> + * The bitmap contains all of the functions used in DMA tags,
including the
>> + * actual device.
>> + * See https://bugzilla.redhat.com/show_bug.cgi?id=757166,
>> + * https://bugzilla.kernel.org/show_bug.cgi?id=42679
>> + * https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1089768
>> + */
>> +static const struct pci_dev_dma_multi_func_sources {
>> + u16 vendor;
>> + u16 device;
>> + u8 func_map; /* bit map. lsb is fn 0. */
>> +} pci_dev_dma_multi_func_sources[] = {
>> + { PCI_VENDOR_ID_MARVELL_2, 0x9123, (1<<0)|(1<<1)},
>> + { PCI_VENDOR_ID_MARVELL_2, 0x9125, (1<<0)|(1<<1)},
>> + { PCI_VENDOR_ID_MARVELL_2, 0x9128, (1<<0)|(1<<1)},
>> + { PCI_VENDOR_ID_MARVELL_2, 0x9130, (1<<0)|(1<<1)},
>> + { PCI_VENDOR_ID_MARVELL_2, 0x9143, (1<<0)|(1<<1)},
>> + { PCI_VENDOR_ID_MARVELL_2, 0x9172, (1<<0)|(1<<1)},
>> + { 0 }
>> +};
>
>
> Adding another buggy device. I have a Ricoh multifunction device:
>
> 17:00.0 SD Host controller: Ricoh Co Ltd MMC/SD Host Controller
(rev
01)
> 17:00.3 FireWire (IEEE 1394): Ricoh Co Ltd R5C832 PCIe IEEE 1394
> Controller (rev 01)
>
> 17:00.0 0805: 1180:e822 (rev 01)
> 17:00.3 0c00: 1180:e832 (rev 01)
>

The Ricoh device issue has been known for some time and a quirk has
been
available since commit 12ea6cad1c7d046 in June 2012. It's slightly
different than the problem this patch tries to work around [1].


Hmm, I've had this problem with many recent (vanilla) kernels, up to and
including 3.9-rc5


> that adding entries for also fixed booting. I don't have any SD
cards or firewire devices handy to test that they work, but the system
now boots, which was not the case without your patch and IOMMU/DMAR
enabled.

That is really strange. Could you tell us what kernel version you
tested
and provide dmesg output?


I'll capture a vanilla 3.8.5 boot without any patches and iommu=off,
then
try to find another machine to catch what I can of a netconsole boot
with
iommu=on. What's the preferred way to send these? pastebin links?

I'd been running the 'dirty' fix that's in the redhat bugzilla entry. I
checked my .config and have CONFIG_PCI_QUIRKS=y, and verified my
devices are
in the quirks table for the pci_func_0_dma_source fixup.

Do you mean that even though your hardware is specifically listed in
the quirk table, the quirk simply hasn't worked for you? That would be
unfortunate, to say the least.

Precisely.

The fedora kernel included a separate patch for this issue until
recently (see https://bugzilla.redhat.com/show_bug.cgi?id=880051). It
basically just disabled DMAR when the Ricoh device is present, the
same as the patch to the mailing list you mentioned.

Yes, that's what I've been avoiding doing. Every new release, I boot
once with iommu=on, and firewire blacklisted, boot up, load the firewire
driver. This has caused the 'Ricoh DMAR' bug on every kernel since I
got the laptop. I then reboot and ....

Is the dirty fix you're referring to comment 7?
https://bugzilla.redhat.com/show_bug.cgi?id=605888#c7

Apply this patch, which has worked fine for me, but per a commend in a
thread I created here on 10/19/2012[1], this has a potential significant
performance impact. In my use case, a performance hit is worth the cost
for the features.

However, your patch(while not intended to be the fix), actually solves
the issue on my machine. I don't know if it also has the potential
performance impact, but it's certainly not noticeably worse in my use case.

Pat Erley

[1] http://marc.info/?l=linux-pci&m=135094489232548&w=2

As a follow up, I still have this problem in 3.10.0-rc1+ (and the patch by Andrew to fix buggy dma source devices still fixes it).

Andrew, have you done anything with your DMA source patch since you last posted it? I'm still using it and it still makes my computer happy. I'd happily switch to a newer revision of the patch instead of carrying a rebased version of what you posted in March.

Pat Erley

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