2 files changed, 35 insertions, 0 deletions

diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index ecc9b66c03cd..01132ac74eb8 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/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 @@ halt:
                 /* 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/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index 0042deb671dd..9aba560fd569 100644
--- a/drivers/usb/host/ehci.h
+++ b/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 */