Provided by:
linux-doc-2.6.15_2.6.15-23.39_all 
NAME
ata_eng_timeout - Handle timeout of queued command
SYNOPSIS
void ata_eng_timeout (struct ata_port * ap);
ARGUMENTS
ap Port on which timed-out command is active
DESCRIPTION
Some part of the kernel (currently, only the SCSI layer) has noticed
that the active command on port ap has not completed after a specified
length of time. Handle this condition by disabling DMA (if necessary)
and completing transactions, with error if necessary.
This also handles the case of the ‘‘lost interrupt’’, where for some
reason (possibly hardware bug, possibly driver bug) an interrupt was
not delivered to the driver, even though the transaction completed
successfully.
LOCKING
Inherited from SCSI layer (none, can sleep)
AUTHOR
Jeff Garzik.