path: root/drivers/usb/host/xhci-ring.c
diff options
authorMathias Nyman <mathias.nyman@linux.intel.com>2013-08-30 18:25:49 +0300
committerSarah Sharp <sarah.a.sharp@linux.intel.com>2013-09-23 15:43:30 -0700
commitec7e43e2d98173483866fe2e4e690143626b659c (patch)
tree43ac59451086b752caee4930129bc7d3ec380117 /drivers/usb/host/xhci-ring.c
parent284d20552461466b04d6bfeafeb1c47a8891b591 (diff)
xhci: Ensure a command structure points to the correct trb on the command ring
If a command on the command ring needs to be cancelled before it is handled it can be turned to a no-op operation when the ring is stopped. We want to store the command ring enqueue pointer in the command structure when the command in enqueued for the cancellation case. Some commands used to store the command ring dequeue pointers instead of enqueue (these often worked because enqueue happends to equal dequeue quite often) Other commands correctly used the enqueue pointer but did not check if it pointed to a valid trb or a link trb, this caused for example stop endpoint command to timeout in xhci_stop_device() in about 2% of suspend/resume cases. This should also solve some weird behavior happening in command cancellation cases. This patch is based on a patch submitted by Sarah Sharp to linux-usb, but then forgotten: http://marc.info/?l=linux-usb&m=136269803207465&w=2 This patch should be backported to kernels as old as 3.7, that contain the commit b92cc66c047ff7cf587b318fe377061a353c120f "xHCI: add aborting command ring function" Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/usb/host/xhci-ring.c')
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index aaa2906f7b78..9ac9672d4498 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -123,6 +123,16 @@ static int enqueue_is_link_trb(struct xhci_ring *ring)
return TRB_TYPE_LINK_LE32(link->control);
+union xhci_trb *xhci_find_next_enqueue(struct xhci_ring *ring)
+ /* Enqueue pointer can be left pointing to the link TRB,
+ * we must handle that
+ */
+ if (TRB_TYPE_LINK_LE32(ring->enqueue->link.control))
+ return ring->enq_seg->next->trbs;
+ return ring->enqueue;
/* Updates trb to point to the next TRB in the ring, and updates seg if the next
* TRB is in a new segment. This does not skip over link TRBs, and it does not
* effect the ring dequeue or enqueue pointers.