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authorSarah Sharp <sarah.a.sharp@linux.intel.com>2011-02-23 15:46:42 -0800
committerSarah Sharp <sarah.a.sharp@linux.intel.com>2011-03-13 18:23:53 -0700
commitbf161e85fb153c0dd5a95faca73fd6a9d237c389 (patch)
tree950c8f7048754e0603e516b295badb869e832e2d /drivers/usb/host/xhci-ring.c
parent0c9ffe0f6286a02bf82f8d7fb7274aec2ad977f1 (diff)
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xhci: Update internal dequeue pointers after stalls.
When an endpoint stalls, the xHCI driver must move the endpoint ring's dequeue pointer past the stalled transfer. To do that, the driver issues a Set TR Dequeue Pointer command, which will complete some time later. Takashi was having issues with USB 1.1 audio devices that stalled, and his analysis of the code was that the old code would not update the xHCI driver's ring dequeue pointer after the command completes. However, the dequeue pointer is set in xhci_find_new_dequeue_state(), just before the set command is issued to the hardware. Setting the dequeue pointer before the Set TR Dequeue Pointer command completes is a dangerous thing to do, since the xHCI hardware can fail the command. Instead, store the new dequeue pointer in the xhci_virt_ep structure, and update the ring's dequeue pointer when the Set TR dequeue pointer command completes. While we're at it, make sure we can't queue another Set TR Dequeue Command while the first one is still being processed. This just won't work with the internal xHCI state code. I'm still not sure if this is the right thing to do, since we might have a case where a driver queues multiple URBs to a control ring, one of the URBs Stalls, and then the driver tries to cancel the second URB. There may be a race condition there where the xHCI driver might try to issue multiple Set TR Dequeue Pointer commands, but I would have to think very hard about how the Stop Endpoint and cancellation code works. Keep the fix simple until when/if we run into that case. This patch should be queued to kernels all the way back to 2.6.31. Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Tested-by: Takashi Iwai <tiwai@suse.de> Cc: stable@kernel.org
Diffstat (limited to 'drivers/usb/host/xhci-ring.c')
-rw-r--r--drivers/usb/host/xhci-ring.c29
1 files changed, 26 insertions, 3 deletions
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index bd0f234..3577cd6 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -501,9 +501,6 @@ void xhci_find_new_dequeue_state(struct xhci_hcd *xhci,
addr = xhci_trb_virt_to_dma(state->new_deq_seg, state->new_deq_ptr);
xhci_dbg(xhci, "New dequeue pointer = 0x%llx (DMA)\n",
(unsigned long long) addr);
- xhci_dbg(xhci, "Setting dequeue pointer in internal ring state.\n");
- ep_ring->dequeue = state->new_deq_ptr;
- ep_ring->deq_seg = state->new_deq_seg;
}
static void td_to_noop(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
@@ -945,9 +942,26 @@ static void handle_set_deq_completion(struct xhci_hcd *xhci,
} else {
xhci_dbg(xhci, "Successful Set TR Deq Ptr cmd, deq = @%08llx\n",
ep_ctx->deq);
+ if (xhci_trb_virt_to_dma(dev->eps[ep_index].queued_deq_seg,
+ dev->eps[ep_index].queued_deq_ptr) ==
+ (ep_ctx->deq & ~(EP_CTX_CYCLE_MASK))) {
+ /* Update the ring's dequeue segment and dequeue pointer
+ * to reflect the new position.
+ */
+ ep_ring->deq_seg = dev->eps[ep_index].queued_deq_seg;
+ ep_ring->dequeue = dev->eps[ep_index].queued_deq_ptr;
+ } else {
+ xhci_warn(xhci, "Mismatch between completed Set TR Deq "
+ "Ptr command & xHCI internal state.\n");
+ xhci_warn(xhci, "ep deq seg = %p, deq ptr = %p\n",
+ dev->eps[ep_index].queued_deq_seg,
+ dev->eps[ep_index].queued_deq_ptr);
+ }
}
dev->eps[ep_index].ep_state &= ~SET_DEQ_PENDING;
+ dev->eps[ep_index].queued_deq_seg = NULL;
+ dev->eps[ep_index].queued_deq_ptr = NULL;
/* Restart any rings with pending URBs */
ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
}
@@ -3283,6 +3297,7 @@ static int queue_set_tr_deq(struct xhci_hcd *xhci, int slot_id,
u32 trb_ep_index = EP_ID_FOR_TRB(ep_index);
u32 trb_stream_id = STREAM_ID_FOR_TRB(stream_id);
u32 type = TRB_TYPE(TRB_SET_DEQ);
+ struct xhci_virt_ep *ep;
addr = xhci_trb_virt_to_dma(deq_seg, deq_ptr);
if (addr == 0) {
@@ -3291,6 +3306,14 @@ static int queue_set_tr_deq(struct xhci_hcd *xhci, int slot_id,
deq_seg, deq_ptr);
return 0;
}
+ ep = &xhci->devs[slot_id]->eps[ep_index];
+ if ((ep->ep_state & SET_DEQ_PENDING)) {
+ xhci_warn(xhci, "WARN Cannot submit Set TR Deq Ptr\n");
+ xhci_warn(xhci, "A Set TR Deq Ptr command is pending.\n");
+ return 0;
+ }
+ ep->queued_deq_seg = deq_seg;
+ ep->queued_deq_ptr = deq_ptr;
return queue_command(xhci, lower_32_bits(addr) | cycle_state,
upper_32_bits(addr), trb_stream_id,
trb_slot_id | trb_ep_index | type, false);