From 3f223a1845337f1d8be7695bb8bff12081acfb92 Mon Sep 17 00:00:00 2001
From: Alan Stern <stern@rowland.harvard.edu>
Date: Tue, 10 Feb 2009 10:16:58 -0500
Subject: [PATCH] --- yaml --- r: 133509 b: refs/heads/master c:
 a2c2706e1043c17139c2dafd171c4a5cf008ef7e h: refs/heads/master i:   133507:
 2addfdc3acc346b8dd29e576399baccac35a2e4d v: v3

---
 [refs]                          |  2 +-
 trunk/drivers/usb/host/ehci-q.c | 32 ++++++++++++++++++++++++++++++++
 trunk/drivers/usb/host/ehci.h   |  3 +++
 3 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 385cf5f04083..c3eabda69695 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 1f4159c1620f74377e26d8a569d10ca5907ef475
+refs/heads/master: a2c2706e1043c17139c2dafd171c4a5cf008ef7e
diff --git a/trunk/drivers/usb/host/ehci-q.c b/trunk/drivers/usb/host/ehci-q.c
index ecc9b66c03cd..01132ac74eb8 100644
--- a/trunk/drivers/usb/host/ehci-q.c
+++ b/trunk/drivers/usb/host/ehci-q.c
@@ -333,12 +333,40 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
 		token = hc32_to_cpu(ehci, qtd->hw_token);
 
 		/* always clean up qtds the hc de-activated */
+ retry_xacterr:
 		if ((token & QTD_STS_ACTIVE) == 0) {
 
 			/* on STALL, error, and short reads this urb must
 			 * complete and all its qtds must be recycled.
 			 */
 			if ((token & QTD_STS_HALT) != 0) {
+
+				/* retry transaction errors until we
+				 * reach the software xacterr limit
+				 */
+				if ((token & QTD_STS_XACT) &&
+						QTD_CERR(token) == 0 &&
+						--qh->xacterrs > 0 &&
+						!urb->unlinked) {
+					ehci_dbg(ehci,
+	"detected XactErr len %d/%d retry %d\n",
+	qtd->length - QTD_LENGTH(token), qtd->length,
+	QH_XACTERR_MAX - qh->xacterrs);
+
+					/* reset the token in the qtd and the
+					 * qh overlay (which still contains
+					 * the qtd) so that we pick up from
+					 * where we left off
+					 */
+					token &= ~QTD_STS_HALT;
+					token |= QTD_STS_ACTIVE |
+							(EHCI_TUNE_CERR << 10);
+					qtd->hw_token = cpu_to_hc32(ehci,
+							token);
+					wmb();
+					qh->hw_token = cpu_to_hc32(ehci, token);
+					goto retry_xacterr;
+				}
 				stopped = 1;
 
 			/* magic dummy for some short reads; qh won't advance.
@@ -421,6 +449,9 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
 		/* remove qtd; it's recycled after possible urb completion */
 		list_del (&qtd->qtd_list);
 		last = qtd;
+
+		/* reinit the xacterr counter for the next qtd */
+		qh->xacterrs = QH_XACTERR_MAX;
 	}
 
 	/* last urb's completion might still need calling */
@@ -862,6 +893,7 @@ static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
 	head->qh_next.qh = qh;
 	head->hw_next = dma;
 
+	qh->xacterrs = QH_XACTERR_MAX;
 	qh->qh_state = QH_STATE_LINKED;
 	/* qtd completions reported later by interrupt */
 }
diff --git a/trunk/drivers/usb/host/ehci.h b/trunk/drivers/usb/host/ehci.h
index 0042deb671dd..9aba560fd569 100644
--- a/trunk/drivers/usb/host/ehci.h
+++ b/trunk/drivers/usb/host/ehci.h
@@ -342,6 +342,9 @@ struct ehci_qh {
 #define	QH_STATE_UNLINK_WAIT	4		/* LINKED and on reclaim q */
 #define	QH_STATE_COMPLETING	5		/* don't touch token.HALT */
 
+	u8			xacterrs;	/* XactErr retry counter */
+#define	QH_XACTERR_MAX		32		/* XactErr retry limit */
+
 	/* periodic schedule info */
 	u8			usecs;		/* intr bandwidth */
 	u8			gap_uf;		/* uframes split/csplit gap */