Tejun Heo wrote:

sata_promise uses two different command modes - packet and TF.  Packet
mode is intelligent low-overhead mode while TF is the same old
taskfile interface.  As with other advanced interface (ahci/sil24),
ATA_TFLAG_POLLING has no effect in packet mode.  However, PIO commands
are issued using TF interface in polling mode, so pdc_interrupt()
considers interrupts spurious if ATA_TFLAG_POLLING is set.

This is broken for polling NODATA commands because command is issued
using packet mode but the interrupt handler ignores it due to
ATA_TFLAG_POLLING.  Fix pdc_qc_issue_prot() such that ATA/ATAPI NODATA
commands are issued using TF interface if ATA_TFLAG_POLLING is set.

This patch fixes detection failure introduced by polling SETXFERMODE.

Signed-off-by: Tejun Heo <redacted>

Eeeek... Wrong thread.  Please ignore this posting.  Will repost.  Sorry.

-- 
tejun