libata: implement ATA_DFLAG_DUBIOUS_XFER
ATA_DFLAG_DUBIOUS_XFER is set whenever data transfer speed or method
changes and gets cleared when data transfer command succeeds in the
newly configured transfer mode.
This will be used to improve speed down logic.
Signed-off-by: Tejun Heo <htejun@gmail.com<
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 86c10cc..124b6f1 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5797,6 +5797,22 @@
ap->ops->tf_read(ap, &qc->result_tf);
}
+static void ata_verify_xfer(struct ata_queued_cmd *qc)
+{
+ struct ata_device *dev = qc->dev;
+
+ if (ata_tag_internal(qc->tag))
+ return;
+
+ if (ata_is_nodata(qc->tf.protocol))
+ return;
+
+ if ((dev->mwdma_mask || dev->udma_mask) && ata_is_pio(qc->tf.protocol))
+ return;
+
+ dev->flags &= ~ATA_DFLAG_DUBIOUS_XFER;
+}
+
/**
* ata_qc_complete - Complete an active ATA command
* @qc: Command to complete
@@ -5868,6 +5884,9 @@
break;
}
+ if (unlikely(dev->flags & ATA_DFLAG_DUBIOUS_XFER))
+ ata_verify_xfer(qc);
+
__ata_qc_complete(qc);
} else {
if (qc->flags & ATA_QCFLAG_EH_SCHEDULED)