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Commit 4b10e559 authored by Tejun Heo's avatar Tejun Heo Committed by Jeff Garzik
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[PATCH] ahci: enable prefetching for PACKET commands 



Turn on AHCI_CMD_PREFETCH for PACKET commands.  This hints the
controller that it can prefetch the CDB and the PRD entries.  This
patch is originally from Jeff Garzik.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 418dc1f5

drivers/scsi/ahci.c

+2 −1
Original line number Diff line number Diff line
@@ -66,6 +66,7 @@ enum { 
	AHCI_IRQ_ON_SG		= (1 << 31),

	AHCI_CMD_ATAPI		= (1 << 5),

	AHCI_CMD_WRITE		= (1 << 6),

	AHCI_CMD_PREFETCH	= (1 << 7),

	AHCI_CMD_RESET		= (1 << 8),

	AHCI_CMD_CLR_BUSY	= (1 << 10),
@@ -631,7 +632,7 @@ static void ahci_qc_prep(struct ata_queued_cmd *qc) 
	if (qc->tf.flags & ATA_TFLAG_WRITE)

		opts |= AHCI_CMD_WRITE;

	if (is_atapi)

		opts |= AHCI_CMD_ATAPI;

		opts |= AHCI_CMD_ATAPI | AHCI_CMD_PREFETCH;



	ahci_fill_cmd_slot(pp, opts);

}