Re: [PATCH V2 1/3] scsi: mptxsas: try 64 bit DMA when 32 bit DMA fails

Sinan Kaya
2015-11-10T20:26:02Z

On 11/10/2015 3:05 PM, James Bottomley wrote:
> OK, you don't seem to be understanding the problem: the Altix isn't a
> LSI card, it was a SGI platform.

Got it.

> It was the platform where we first
> discovered the issue that a lot of storage cards didn't work because it
> by default had no memory below 4GB. The reason coherent masks were
> introduced was initially so the Altix could manufacture and manage a
> region of memory in the lower 4GB region and we would guarantee to make
> allocations from it so the storage cards would then work on that
> platform.

I can't fix the issue if the card cannot do 64 bit DMA when IOMMU is not
there. I need IOMMU enabled all the time for this card.

--
Sinan Kaya
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a
Linux Foundation Collaborative Project