[PATCH] xhci-hub.c: handle command_trb that may be link TRB

[Xiao Jin]

From: xiao jin <jin.xiao@xxxxxxxxx>
Date: Wed, 9 Oct 2013 09:38:45 +0800
Subject: [PATCH] xhci-hub.c: handle command_trb that may be link TRB

When xhci stop device, it's possible cmd_ring enqueue point to
link TRB after queue the last but one stop endpoint. We must
handle the command_trb point to the next segment trb. Otherwise
xhci stop devie will timeout because command_trb can't match
with cmd_ring dequeue.

The patch is to let command_trb point to the next segment trb if
cmd_ring enqueue point to link TRB.

Signed-off-by: xiao jin <jin.xiao@xxxxxxxxx>
---
 drivers/usb/host/xhci-hub.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 1d35459..4872640 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -287,6 +287,13 @@ static int xhci_stop_device(struct xhci_hcd *xhci, int slot_id, int suspend)
 			xhci_queue_stop_endpoint(xhci, slot_id, i, suspend);
 	}
 	cmd->command_trb = xhci->cmd_ring->enqueue;
+	/* Enqueue pointer can be left pointing to the link TRB,
+	 * we must handle that
+	 */
+	if (TRB_TYPE_LINK_LE32(cmd->command_trb->link.control))
+		cmd->command_trb =
+			xhci->cmd_ring->enq_seg->next->trbs;
+
 	list_add_tail(&cmd->cmd_list, &virt_dev->cmd_list);
 	xhci_queue_stop_endpoint(xhci, slot_id, 0, suspend);
 	xhci_ring_cmd_db(xhci);
-- 
1.7.1



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