Intel xhci: Ignore spurious successful event.

The xHCI host controller in the Panther Point chipset sometimes produces
spurious events on the event ring.  If it receives a short packet, it
first puts a Transfer Event with a short transfer completion code on the
event ring.  Then it puts a Transfer Event with a successful completion
code on the ring for the same TD.  The xHCI driver correctly processes the
short transfer completion code, gives the URB back to the driver, and then
prints a warning in dmesg about the spurious event.  These warning
messages really fill up dmesg when an HD webcam is plugged into xHCI.

This spurious successful event behavior isn't technically disallowed by
the xHCI specification, so make the xHCI driver just ignore the spurious
completion event.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index faf039ac6573d5be80a39439a2cd94ce6ac89dbb..eafd17fae949d1ac942e3c2bbc3e4f22da7e3b4b 100644 (file)
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -118,6 +118,10 @@ static int xhci_pci_setup(struct usb_hcd *hcd)
        /* AMD PLL quirk */
        if (pdev->vendor == PCI_VENDOR_ID_AMD && usb_amd_find_chipset_info())
                xhci->quirks |= XHCI_AMD_PLL_FIX;
+       if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
+                       pdev->device == PCI_DEVICE_ID_INTEL_PANTHERPOINT_XHCI) {
+               xhci->quirks |= XHCI_SPURIOUS_SUCCESS;
+       }
 
        /* Make sure the HC is halted. */
        retval = xhci_halt(xhci);

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index d1498c03c4cbfba27dfab25173a6b41d0c9ac54d..56f6c584c651a0f5763f459c49d98cc261ba593e 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2061,6 +2061,16 @@ static int handle_tx_event(struct xhci_hcd *xhci,
                if (!event_seg) {
                        if (!ep->skip ||
                            !usb_endpoint_xfer_isoc(&td->urb->ep->desc)) {
+                               /* Some host controllers give a spurious
+                                * successful event after a short transfer.
+                                * Ignore it.
+                                */
+                               if ((xhci->quirks & XHCI_SPURIOUS_SUCCESS) && 
+                                               ep_ring->last_td_was_short) {
+                                       ep_ring->last_td_was_short = false;
+                                       ret = 0;
+                                       goto cleanup;
+                               }
                                /* HC is busted, give up! */
                                xhci_err(xhci,
                                        "ERROR Transfer event TRB DMA ptr not "
@@ -2071,6 +2081,10 @@ static int handle_tx_event(struct xhci_hcd *xhci,
                        ret = skip_isoc_td(xhci, td, event, ep, &status);
                        goto cleanup;
                }
+               if (trb_comp_code == COMP_SHORT_TX)
+                       ep_ring->last_td_was_short = true;
+               else
+                       ep_ring->last_td_was_short = false;
 
                if (ep->skip) {
                        xhci_dbg(xhci, "Found td. Clear skip flag.\n");

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 0772a8cfea230c2c79a52434dc28da76bbd86eaa..5cfeb8614b87e1ff8f4e06b830b005e6437b575b 100644 (file)
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1123,6 +1123,7 @@ struct xhci_ring {
         */
        u32                     cycle_state;
        unsigned int            stream_id;
+       bool                    last_td_was_short;
 };
 
 struct xhci_erst_entry {
@@ -1290,6 +1291,7 @@ struct xhci_hcd {
 #define XHCI_RESET_EP_QUIRK    (1 << 1)
 #define XHCI_NEC_HOST          (1 << 2)
 #define XHCI_AMD_PLL_FIX       (1 << 3)
+#define XHCI_SPURIOUS_SUCCESS  (1 << 4)
        /* There are two roothubs to keep track of bus suspend info for */
        struct xhci_bus_state   bus_state[2];
        /* Is each xHCI roothub port a USB 3.0, USB 2.0, or USB 1.1 port? */