Re: ath9k and AMD IOMMU alias breakage on 3.16?

On Fri, 2014-09-05 at 20:00 -0700, Jason Newton wrote:

Hi,

I have an AR9462 connected over minipcie, it came with the ASRock
FM2A88x-itx motherboard and I'm using an AMD A10-7850K cpu with it.  When I
have IOMMU enabled, and this is desirable for opencl related things, the
AR9462 malfunctions with these two errors occurring:

AMD-Vi: Event logged [INVALID_DEVICE_REQUEST device=00:00.1
address=0x000000fdf8080020 flags=0x0a00]

Followed by this  looping error, which reoccurs shortly after associating
and obtaining an IP.  I've attached a large snippet from dmesg, due to it's
length.

I'm not sure where the error is coming from but I did see that Alex
Williamson posted a patch that dealt with aliased devices (like pci
bridges) and AMD's IOMMU issues, see
e028a9e6b8a637af09ac4114083280df4a7045f1 for reference.

I then disable IOMMU in the bios, and immediately the ath9k/AR9462 pair is
working without flaw or retries.  Bios is up to date btw, updated it after
building the machine last friday.

So anyone have a clue what's going on here?

Please boot with "amd_iommu_dump" on the kernel boot line and send the
full dmesg log and 'sudo lspci -vvv' output.  Thanks,

Alex