mpt2sas DMA mask

Brian King brking at
Wed May 13 08:07:36 AEST 2015

The mpt2sas driver was changed late last year in that it now requests a 64 bit DMA
mask, then requests a 32 bit coherent DMA mask, then later requests a 64 bit coherent
DMA mask. This was 5fb1bf8aaa832e1e9ca3198de7bbecb8eff7db9c. This breaks 64 bit DMA
support for mpt2sas on Power and we always fall back to using 32 bit DMA. Looking
at the commit log, it looks like this was an intentional change.

Ben - you had a patch set you had posted to the list back in Feb of this year, but it
doesn't look like it got merged.

This would fix the issue I'm seeing on mpt2sas. Do you plan to dust that patch set
off and upstream it? Were there issues with it that still need to be resolved?



Brian King
Power Linux I/O
IBM Linux Technology Center

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