libata-pmp: clear hob for pmp register accesses
>> Mark Lord wrote: >>> Tejun, I've added PMP to sata_mv, and am now trying to get it >>> to work with a Marvell PM attached. > >>> And the behaviour I see is very bizarre. >>> After hard+soft resets, the PM signature is found, >>> and libata interrogates the PM registers. >>> >>> It successfully reads register 0, and then register 1. >>> But all subsequent registers read out (incorrectly) as zeros. ... This behavior has been confirmed by Marvell with a SATA analyzer. The Marvell port-multiplier apparently likes to see clean HOB information when accessing PMP registers. Since sata_mv uses PIO shadow register access, this doesn't happen automatically, as it might in a more purely FIS-based driver (eg. ahci). One way to fix this is to flag these commands with ATA_TFLAG_LBA48, forcing libata to write out the HOB fields with known (zero) values. Signed-off-by: Saeed Bishara <saeed@marvell.com> Acked-by: Mark Lord <mlord@pobox.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
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