From 10830029310fdcbbdae9d7c23da886ab7d9e580a Mon Sep 17 00:00:00 2001
From: Gwendal Grignou <gwendal@google.com>
Date: Mon, 12 Oct 2009 15:44:00 -0700
Subject: [PATCH] --- yaml --- r: 167646 b: refs/heads/master c:
 159a7ff7a13f9a02c75006f40c0561a3a81aefcd h: refs/heads/master v: v3

---
 [refs]                      |  2 +-
 trunk/drivers/ata/sata_mv.c | 29 +++++++++++++++++++++++++++--
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/[refs] b/[refs]
index b9fc0bf3f267..c6482b6fb0e3 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 6d4f950e9ea15816c6a4f266ce6b9e438346771e
+refs/heads/master: 159a7ff7a13f9a02c75006f40c0561a3a81aefcd
diff --git a/trunk/drivers/ata/sata_mv.c b/trunk/drivers/ata/sata_mv.c
index 17f9ff9067a2..6f5093b7c8c5 100644
--- a/trunk/drivers/ata/sata_mv.c
+++ b/trunk/drivers/ata/sata_mv.c
@@ -1382,6 +1382,25 @@ static int mv_qc_defer(struct ata_queued_cmd *qc)
 	 */
 	if (pp->pp_flags & MV_PP_FLAG_DELAYED_EH)
 		return ATA_DEFER_PORT;
+
+	/* PIO commands need exclusive link: no other commands [DMA or PIO]
+	 * can run concurrently.
+	 * set excl_link when we want to send a PIO command in DMA mode
+	 * or a non-NCQ command in NCQ mode.
+	 * When we receive a command from that link, and there are no
+	 * outstanding commands, mark a flag to clear excl_link and let
+	 * the command go through.
+	 */
+	if (unlikely(ap->excl_link)) {
+		if (link == ap->excl_link) {
+			if (ap->nr_active_links)
+				return ATA_DEFER_PORT;
+			qc->flags |= ATA_QCFLAG_CLEAR_EXCL;
+			return 0;
+		} else
+			return ATA_DEFER_PORT;
+	}
+
 	/*
 	 * If the port is completely idle, then allow the new qc.
 	 */
@@ -1395,8 +1414,14 @@ static int mv_qc_defer(struct ata_queued_cmd *qc)
 	 * doesn't allow it.
 	 */
 	if ((pp->pp_flags & MV_PP_FLAG_EDMA_EN) &&
-	    (pp->pp_flags & MV_PP_FLAG_NCQ_EN) && ata_is_ncq(qc->tf.protocol))
-		return 0;
+	    (pp->pp_flags & MV_PP_FLAG_NCQ_EN)) {
+		if (ata_is_ncq(qc->tf.protocol))
+			return 0;
+		else {
+			ap->excl_link = link;
+			return ATA_DEFER_PORT;
+		}
+	}
 
 	return ATA_DEFER_PORT;
 }