Re: [PATCH 2.6.22.y] ieee1394: revert "sbp2: enforce 32bit DMA mapping"

On Mon, 2007-08-06 at 13:58 +0200, Olaf Hering wrote:

On Sun, Aug 05, Stefan Richter wrote:

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Benjamin Herrenschmidt wrote:

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If setting 32-bit DMA mask fails on ppc64, that sounds like a problem
with the DMA implementation on that architecture. There are enough cards
out there that only support 32-bit DMA that this really needs to work..

Yes, could the PPC folks please have a look at it?  Thanks.

Smells like we may have a bug there. No worries though, all current PPC
machines have an iommu that will not give out addresses above 32 bits
anyway, but I'll double check what's up.

Do you see something in dmesg when that happens ?

There was nothing in Olaf's report, except for trouble in sbp2 _after_
the failure.  http://lkml.org/lkml/2007/8/1/344  (I don't have a PMac.)

sbp2util_remove_command_orb_pool() does not check for lu->hi being NULL.

dev->dma_mask is NULL too, thats why dma_direct_dma_supported() returns
false, and dma_set_mask() will return -EIO.

Strange... PCI devices should never have a NULL dma mask. I wonder how
we get there... 

Ben.