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authorMichal Pecio <michal.pecio@gmail.com>2025-03-11 17:45:51 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-05-02 07:59:18 +0200
commit9ff59cb815007151b6d104e983e1af4a82995eeb (patch)
tree393d74221564a6e605876bab9f492b89ff671d1b
parent2ef4b0e9117056708d7310f80867779f019c065f (diff)
usb: xhci: Avoid Stop Endpoint retry loop if the endpoint seems Running
[ Upstream commit 28a76fcc4c85dd39633fb96edb643c91820133e3 ] 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> Signed-off-by: Sasha Levin <sashal@kernel.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 653e24bb3e9a..cb2a04721307 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1190,16 +1190,19 @@ static void xhci_handle_cmd_stop_ep(struct xhci_hcd *xhci, int slot_id,
* 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) {