[3.19.y-ckt stable] Patch "xhci: fix isoc endpoint dequeue from advancing too far on transaction error" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    xhci: fix isoc endpoint dequeue from advancing too far on transaction error

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt2.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 38d17706d2ccbb0a2dec748c180b4b5b2daa7b0a Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman at linux.intel.com>
Date: Thu, 30 Apr 2015 17:16:02 +0300
Subject: xhci: fix isoc endpoint dequeue from advancing too far on transaction
 error

commit d104d0152a97fade389f47635b73a9ccc7295d0b upstream.

Isoc TDs usually consist of one TRB, sometimes two. When all goes well we
receive only one success event for a TD, and move the dequeue pointer to
the next TD.

This fails if the TD consists of two TRBs and we get a transfer error
on the first TRB, we will then see two events for that TD.

Fix this by making sure the event we get is for the last TRB in that TD
before moving the dequeue pointer to the next TD. This will resolve some
of the uvc and dvb issues with the
"ERROR Transfer event TRB DMA ptr not part of current TD" error message

Signed-off-by: Mathias Nyman <mathias.nyman at linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/host/xhci-ring.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 7dd25ce..893cdf1 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2026,8 +2026,13 @@ static int process_isoc_td(struct xhci_hcd *xhci, struct xhci_td *td,
 		break;
 	case COMP_DEV_ERR:
 	case COMP_STALL:
+		frame->status = -EPROTO;
+		skip_td = true;
+		break;
 	case COMP_TX_ERR:
 		frame->status = -EPROTO;
+		if (event_trb != td->last_trb)
+			return 0;
 		skip_td = true;
 		break;
 	case COMP_STOP:
--
1.9.1