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authorMichal Pecio <michal.pecio@gmail.com>2025-03-11 17:45:51 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-03-11 17:58:43 +0100
commit28a76fcc4c85dd39633fb96edb643c91820133e3 (patch)
treecf7635260f4f8469ec1156954051adceed793c78
parentusb: xhci: Don't change the status of stalled TDs on failed Stop EP (diff)
downloadwireguard-linux-28a76fcc4c85dd39633fb96edb643c91820133e3.tar.xz
wireguard-linux-28a76fcc4c85dd39633fb96edb643c91820133e3.zip
usb: xhci: Avoid Stop Endpoint retry loop if the endpoint seems Running
Nothing prevents a broken HC from claiming that an endpoint is Running and repeatedly rejecting Stop Endpoint with Context State Error. Avoid infinite retries and give back cancelled TDs. No such cases known so far, but HCs have bugs. Signed-off-by: Michal Pecio <michal.pecio@gmail.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/20250311154551.4035726-4-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/usb/host/xhci-ring.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 303d66df271e..5d64c297721c 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1264,16 +1264,19 @@ reset_done:
* Stopped state, but it will soon change to Running.
*
* Assume this bug on unexpected Stop Endpoint failures.
- * Keep retrying until the EP starts and stops again, on
- * chips where this is known to help. Wait for 100ms.
+ * Keep retrying until the EP starts and stops again.
*/
- if (time_is_before_jiffies(ep->stop_time + msecs_to_jiffies(100)))
- break;
fallthrough;
case EP_STATE_RUNNING:
/* Race, HW handled stop ep cmd before ep was running */
xhci_dbg(xhci, "Stop ep completion ctx error, ctx_state %d\n",
GET_EP_CTX_STATE(ep_ctx));
+ /*
+ * Don't retry forever if we guessed wrong or a defective HC never starts
+ * the EP or says 'Running' but fails the command. We must give back TDs.
+ */
+ if (time_is_before_jiffies(ep->stop_time + msecs_to_jiffies(100)))
+ break;
command = xhci_alloc_command(xhci, false, GFP_ATOMIC);
if (!command) {