COMP_SUCCESS should only be asserted on a *true* sucessful transfer. Any
other cases are bogus and we should aim to catch them. One easy way to
get bug reports is to trigger a WARN_ONCE() on such cases.

Signed-off-by: Felipe Balbi <felipe.ba...@linux.intel.com>
---
 drivers/usb/host/xhci-ring.c | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 17b878b53b46..772e07e2ef16 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1934,6 +1934,7 @@ static int process_ctrl_td(struct xhci_hcd *xhci, struct 
xhci_td *td,
 {
        struct xhci_virt_device *xdev;
        struct xhci_ring *ep_ring;
+       struct device *dev;
        unsigned int slot_id;
        int ep_index;
        struct xhci_ep_ctx *ep_ctx;
@@ -1950,15 +1951,15 @@ static int process_ctrl_td(struct xhci_hcd *xhci, 
struct xhci_td *td,
        trb_comp_code = GET_COMP_CODE(le32_to_cpu(event->transfer_len));
        requested = td->urb->transfer_buffer_length;
        remaining = EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
+       dev = xhci_to_hcd(xhci)->self.controller;
 
        switch (trb_comp_code) {
        case COMP_SUCCESS:
-               if (trb_type != TRB_STATUS) {
-                       xhci_warn(xhci, "WARN: Success on ctrl %s TRB without 
IOC set?\n",
-                                       (trb_type == TRB_DATA) ? "data" : 
"setup");
-                       *status = -ESHUTDOWN;
-                       break;
-               }
+               dev_WARN_ONCE(dev, trb_type != TRB_STATUS,
+                               "ep%d%s: unexpected success! TRB Type %d\n",
+                               usb_endpoint_num(&td->urb->ep->desc),
+                               usb_endpoint_dir_in(&td->urb->ep->desc) ?
+                               "in" : "out", trb_type);
                *status = 0;
                break;
        case COMP_SHORT_PACKET:
@@ -2150,6 +2151,7 @@ static int process_bulk_intr_td(struct xhci_hcd *xhci, 
struct xhci_td *td,
        struct xhci_virt_ep *ep, int *status)
 {
        struct xhci_ring *ep_ring;
+       struct device *dev;
        u32 trb_comp_code;
        u32 remaining, requested, ep_trb_len;
 
@@ -2158,16 +2160,16 @@ static int process_bulk_intr_td(struct xhci_hcd *xhci, 
struct xhci_td *td,
        remaining = EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
        ep_trb_len = TRB_LEN(le32_to_cpu(ep_trb->generic.field[2]));
        requested = td->urb->transfer_buffer_length;
+       dev = xhci_to_hcd(xhci)->self.controller;
 
        switch (trb_comp_code) {
        case COMP_SUCCESS:
-               /* handle success with untransferred data as short packet */
-               if (ep_trb != td->last_trb || remaining) {
-                       xhci_warn(xhci, "WARN Successful completion on short 
TX\n");
-                       xhci_dbg(xhci, "ep %#x - asked for %d bytes, %d bytes 
untransferred\n",
-                                td->urb->ep->desc.bEndpointAddress,
-                                requested, remaining);
-               }
+               dev_WARN_ONCE(dev, (ep_trb != td->last_trb) || remaining,
+                               "ep%d%s: unexpected success! TRB %p/%p size 
%d/%d\n",
+                               usb_endpoint_num(&td->urb->ep->desc),
+                               usb_endpoint_dir_in(&td->urb->ep->desc) ?
+                               "in" : "out", ep_trb, td->last_trb, remaining,
+                               requested);
                *status = 0;
                break;
        case COMP_SHORT_PACKET:
-- 
2.10.1

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