[PATCH] sata_sil24: update TF image only when necessary

Update TF image (pp->tf) only when necessary.

Signed-off-by: Tejun Heo <htejun@gmail.com>

1 files changed, 2 insertions, 10 deletions

diff --git a/drivers/scsi/sata_sil24.c b/drivers/scsi/sata_sil24.c
index 8c167250f4c9..45b9e37c191e 100644
--- a/drivers/scsi/sata_sil24.c
+++ b/drivers/scsi/sata_sil24.c
@@ -799,17 +799,9 @@ static inline void sil24_host_intr(struct ata_port *ap)
                 if (ap->flags & SIL24_FLAG_PCIX_IRQ_WOC)
                         writel(PORT_IRQ_COMPLETE, port + PORT_IRQ_STAT);
 
-                /*
-                 * !HOST_SSAT_ATTN guarantees successful completion,
-                 * so reading back tf registers is unnecessary for
-                 * most commands.  TODO: read tf registers for
-                 * commands which require these values on successful
-                 * completion (EXECUTE DEVICE DIAGNOSTIC, CHECK POWER,
-                 * DEVICE RESET and READ PORT MULTIPLIER (any more?).
-                 */
-                sil24_update_tf(ap);
-
                 if (qc) {
+                        if (qc->flags & ATA_QCFLAG_RESULT_TF)
+                                sil24_update_tf(ap);
                         qc->err_mask |= ac_err_mask(pp->tf.command);
                         ata_qc_complete(qc);
                 }