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authorSarah Sharp <sarah.a.sharp@linux.intel.com>2011-02-23 15:46:42 -0800
committerGreg Kroah-Hartman <gregkh@suse.de>2011-03-23 13:03:51 -0700
commit5fb7c16628c599f9598ebda9403af1c122f1911e (patch)
treef3e162cd903f4a29c50903e8e79dca6817d1565c
parentca81d7760eb900e6f42b60e52b8a3efc88780e37 (diff)
xhci: Update internal dequeue pointers after stalls.
commit bf161e85fb153c0dd5a95faca73fd6a9d237c389 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/usb/host/xhci-ring.c29
-rw-r--r--drivers/usb/host/xhci.h9
2 files changed, 35 insertions, 3 deletions
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 3289bf4832c9..699676d1df88 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -506,9 +506,6 @@ 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,
@@ -951,9 +948,26 @@ 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);
}
@@ -3229,6 +3243,7 @@ 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) {
@@ -3237,6 +3252,14 @@ 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);
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 7f127df6dd55..62bc1bc2bd72 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -644,6 +644,9 @@ struct xhci_ep_ctx {
#define AVG_TRB_LENGTH_FOR_EP(p) ((p) & 0xffff)
#define MAX_ESIT_PAYLOAD_FOR_EP(p) (((p) & 0xffff) << 16)
+/* deq bitmasks */
+#define EP_CTX_CYCLE_MASK (1 << 0)
+
/**
* struct xhci_input_control_context
@@ -746,6 +749,12 @@ struct xhci_virt_ep {
struct timer_list stop_cmd_timer;
int stop_cmds_pending;
struct xhci_hcd *xhci;
+ /* Dequeue pointer and dequeue segment for a submitted Set TR Dequeue
+ * command. We'll need to update the ring's dequeue segment and dequeue
+ * pointer after the command completes.
+ */
+ struct xhci_segment *queued_deq_seg;
+ union xhci_trb *queued_deq_ptr;
/*
* Sometimes the xHC can not process isochronous endpoint ring quickly
* enough, and it will miss some isoc tds on the ring and generate