linux-kernel - [PATCH 3.13.y-ckt 71/96] xhci: handle no ping response error properly

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Message-Id: <1447451390-16480-72-git-send-email-kamal@canonical.com>
Date:	Fri, 13 Nov 2015 13:49:25 -0800
From:	Kamal Mostafa <kamal@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Mathias Nyman <mathias.nyman@...ux.intel.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 3.13.y-ckt 71/96] xhci: handle no ping response error properly

3.13.11-ckt30 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mathias Nyman <mathias.nyman@...ux.intel.com>

commit 3b4739b8951d650becbcd855d7d6f18ac98a9a85 upstream.

If a host fails to wake up a isochronous SuperSpeed device from U1/U2
in time for a isoch transfer it will generate a "No ping response error"
Host will then move to the next transfer descriptor.

Handle this case in the same way as missed service errors, tag the
current TD as skipped and handle it on the next transfer event.

Signed-off-by: Mathias Nyman <mathias.nyman@...ux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
 drivers/usb/host/xhci-ring.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 71cc699..f2f736e 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2453,6 +2453,7 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 	u32 trb_comp_code;
 	int ret = 0;
 	int td_num = 0;
+	bool handling_skipped_tds = false;
 
 	slot_id = TRB_TO_SLOT_ID(le32_to_cpu(event->flags));
 	xdev = xhci->devs[slot_id];
@@ -2586,6 +2587,10 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 		ep->skip = true;
 		xhci_dbg(xhci, "Miss service interval error, set skip flag\n");
 		goto cleanup;
+	case COMP_PING_ERR:
+		ep->skip = true;
+		xhci_dbg(xhci, "No Ping response error, Skip one Isoc TD\n");
+		goto cleanup;
 	default:
 		if (xhci_is_vendor_info_code(xhci, trb_comp_code)) {
 			status = 0;
@@ -2717,13 +2722,18 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 						 ep, &status);
 
 cleanup:
+
+
+		handling_skipped_tds = ep->skip &&
+			trb_comp_code != COMP_MISSED_INT &&
+			trb_comp_code != COMP_PING_ERR;
+
 		/*
-		 * Do not update event ring dequeue pointer if ep->skip is set.
-		 * Will roll back to continue process missed tds.
+		 * Do not update event ring dequeue pointer if we're in a loop
+		 * processing missed tds.
 		 */
-		if (trb_comp_code == COMP_MISSED_INT || !ep->skip) {
+		if (!handling_skipped_tds)
 			inc_deq(xhci, xhci->event_ring);
-		}
 
 		if (ret) {
 			urb = td->urb;
@@ -2758,7 +2768,7 @@ cleanup:
 	 * Process them as short transfer until reach the td pointed by
 	 * the event.
 	 */
-	} while (ep->skip && trb_comp_code != COMP_MISSED_INT);
+	} while (handling_skipped_tds);
 
 	return 0;
 }
-- 
1.9.1

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