>From dd491aae154bdb3805ad823a5776799aaafb7cda Mon Sep 17 00:00:00 2001
From: Andiry Xu <andiry.xu@xxxxxxx>
Date: Mon, 2 Aug 2010 17:35:00 +0800
Subject: [PATCH] xHCI: update ring dequeue pointer when process missed tds
This patch fixes a isoc transfer bug reported by Sander Eikelenboom.
When ep->skip is set, endpoint ring dequeue pointer should be updated
when processed every missed td. Although ring dequeue pointer will also
be updated when ep->skip is clear, leave it intact during missed tds
processing may cause two issues:
1). If the very next valid transfer following missed tds is a short
transfer, its actual_length will be miscalculated;
2). If there are too many missed tds during transfer, new inserted tds
may found the transfer ring full and urb enqueue fails.
Reported-by: Sander Eikelenboom <linux@xxxxxxxxxxxxxx>
Tested-by: Sander Eikelenboom <linux@xxxxxxxxxxxxxx>
Signed-off-by: Andiry Xu <andiry.xu@xxxxxxx>
---
drivers/usb/host/xhci-ring.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index da3519e..f27c599 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1535,6 +1535,10 @@ static int process_isoc_td(struct xhci_hcd *xhci, struct xhci_td *td,
/* calc actual length */
if (ep->skip) {
td->urb->iso_frame_desc[idx].actual_length = 0;
+ /* Update ring dequeue pointer */
+ while (ep_ring->dequeue != td->last_trb)
+ inc_deq(xhci, ep_ring, false);
+ inc_deq(xhci, ep_ring, false);
return finish_td(xhci, td, event_trb, event, ep, status, true);
}
--
1.7.0.4
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