Jeff Garzik wrote:
On Wed, Nov 07, 2007 at 06:36:13PM -0500, Mark Lord wrote:
Mark Lord wrote:
..
and SG_IO WRITEs don't work. That's really no different from
the existing 2.6.24 version. Regular I/O looks fine.
...
I should qualify that: SG_IO *PIO* WRITEs don't work.
SG_IO PIO READs do work, and SG_IO DMA R/W both work.
multi-sector or single-sector PIO?
..
I was issuing single-sector PIO writes for one sector.
Something gets confused somewhere by that.
It really didn't seem worth tracking down further,
as regular kernel initiated I/O is fine (DMA though),
and this chip doesn't have much of a user/testing base.
I suppose it has to do with the initial DRQ interrupt
from a PIO WRITE --> the chip designers actually never
tested anything other than READ and IDENTIFY in register
PIO mode, so it could even be a chip issue.
The full-fledged qstor driver uses the chip's packet mode
for *everything*, including "PIO" R/W, so this is actually
the first time that direct PIO has even been attempted.
No surprise that it might fail.
If the chip were more commonly available/used, then I would
probably update sata_qstor to use packet mode for PIO as well.
But that's more effort than it's worth, really.
Cheers
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