[PATCH 2/5] usb: xhci: reset_ep: wait for real completion, not the caller's timeout

[Stephano Cetola]

reset_ep() recovers a halted endpoint by issuing a Reset Endpoint
command followed by a Set TR Dequeue Pointer command, each followed
by a wait for the command's completion event. It waited using the
caller's timeout_ms.

For an interrupt endpoint poll, timeout_ms is 0 (a non-blocking
check for pending data). Passed through to reset_ep(), that same 0ms
value gives the actual recovery commands almost no time to complete.
xhci_wait_for_event() gives up immediately, reset_ep() returns before
the halt is ever cleared, and the endpoint stays halted forever no
matter how many times the caller retries.

Recovering from a halt is a command completion wait, not a data
transfer wait, and should not inherit the transfer's timeout.

Signed-off-by: Stephano Cetola <stephano at cetola.net>
---
 drivers/usb/host/xhci-ring.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index bd38f0de91..0b11da88a2 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -506,7 +506,7 @@ union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected,
  * Send reset endpoint command for given endpoint. This recovers from a
  * halted endpoint (e.g. due to a stall error).
  */
-static void reset_ep(struct usb_device *udev, int ep_index, unsigned int timeout_ms)
+static void reset_ep(struct usb_device *udev, int ep_index)
 {
 	struct xhci_ctrl *ctrl = xhci_get_ctrl(udev);
 	struct xhci_ring *ring =  ctrl->devs[udev->slot_id]->eps[ep_index].ring;
@@ -517,7 +517,7 @@ static void reset_ep(struct usb_device *udev, int ep_index, unsigned int timeout
 	dev_info(&udev->dev, "Resetting EP %d...\n", ep_index);
 
 	xhci_queue_command(ctrl, 0, udev->slot_id, ep_index, TRB_RESET_EP);
-	event = xhci_wait_for_event(ctrl, TRB_COMPLETION, timeout_ms);
+	event = xhci_wait_for_event(ctrl, TRB_COMPLETION, XHCI_TIMEOUT_DEFAULT);
 	if (!event)
 		return;
 
@@ -528,7 +528,7 @@ static void reset_ep(struct usb_device *udev, int ep_index, unsigned int timeout
 	addr = xhci_trb_virt_to_dma(ring->enq_seg,
 		(void *)((uintptr_t)ring->enqueue | ring->cycle_state));
 	xhci_queue_command(ctrl, addr, udev->slot_id, ep_index, TRB_SET_DEQ);
-	event = xhci_wait_for_event(ctrl, TRB_COMPLETION, timeout_ms);
+	event = xhci_wait_for_event(ctrl, TRB_COMPLETION, XHCI_TIMEOUT_DEFAULT);
 	if (!event)
 		return;
 
@@ -706,7 +706,7 @@ int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
 	 * have dealt with whatever caused the error.
 	 */
 	if ((le32_to_cpu(ep_ctx->ep_info) & EP_STATE_MASK) == EP_STATE_HALTED)
-		reset_ep(udev, ep_index, timeout_ms);
+		reset_ep(udev, ep_index);
 
 	ring = virt_dev->eps[ep_index].ring;
 	/*
@@ -1055,7 +1055,7 @@ int xhci_ctrl_tx(struct usb_device *udev, unsigned long pipe,
 		dma_unmap_single(ctrl->host.hw_dev, map, length, direction);
 
 	if (udev->status == USB_ST_STALLED) {
-		reset_ep(udev, ep_index, timeout_ms);
+		reset_ep(udev, ep_index);
 		return -EPIPE;
 	}
 

-- 
2.55.0