patch "xhci: fix isoc endpoint dequeue from advancing too far on transaction" added to usb-linus

This is a note to let you know that I've just added the patch titled

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

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From: Mathias Nyman <[email protected]>
Date: Thu, 30 Apr 2015 17:16:02 +0300
Subject: xhci: fix isoc endpoint dequeue from advancing too far on transaction
error

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

---
 drivers/usb/host/xhci-ring.c | 5 +++++
 1 file changed, 5 insertions(+)

index f5397a517c54..ae0894c7ee11 100644
@@ -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:

2.4.0