Re: [PATCH] sata_nv: fix ADMA ATAPI issues with memory over 4GB (v3)

[Robert Hancock]

Mark Lord wrote:
> Morrison, Tom wrote:
> > I am hopeful that the sata_mv has this bug (I proved that the
> > problem I was experiencing was due to the sata_mv driver with 3.75Gig 
> > or more of memory)...
> >  
> > I am on vacation for a week or more ...or I'd tell you today
> > if it did have this bug!
> ..
>
> Yeah, I kind of had your reports in mind when I asked that.  :)
>
> On a related note, I now have lots of Marvell (sata_mv) hardware here,
> and an Intel CPU/chipset box with physical RAM above the 4GB boundary.

Based on a quick look at sata_mv it appears it sets a 64-bit DMA mask 
unconditionally, but for non-ATA_PROT_DMA commands (which includes all 
ATAPI), it just falls back to ata_qc_issue_prot which issues via the 
legacy SFF interface and can only handle 32-bit addressing. So yes, it 
appears to have a similar bug as sata_nv had.

Likely it needs a similar slave_config trick to change bounce limit 
depending on the connected device, unless there is really a way to issue 
ATAPI commands with this EDMA interface, as the TODO list in sata_mv.c 
suggests may be possible..

--
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@xxxxxxxxxxxxx
Home Page: http://www.roberthancock.com/

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