If a command event is found on the event ring during an interrupt, we need to stop the command timer with del_timer(). Since del_timer() can fail if the timer is running and waiting on the xHCI lock, then it maybe get the wrong timeout command in xhci_handle_command_timeout() if host fetched a new command and updated the xhci->current_cmd in handle_cmd_completion(). For this situation, we need a way to signal to the command timer that everything is fine and it should exit.
We should check if the command timer is pending in xhci_handle_command_timeout() function, if the command timer is pending, which means current timeout command has been handled by host and host has fetched new command and re-added the command timer, then just return and wait for new current command. If not, it means current command is timeout and need to be handled.
Signed-off-by: Baolin Wang baolin.wang@linaro.org --- Changes since v1: - Remove the counter and just check if the command timer is pending. --- drivers/usb/host/xhci-ring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 9965a4c..3947344 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -1269,7 +1269,7 @@ void xhci_handle_command_timeout(unsigned long data) xhci = (struct xhci_hcd *) data;
spin_lock_irqsave(&xhci->lock, flags); - if (!xhci->current_cmd) { + if (!xhci->current_cmd || timer_pending(&xhci->cmd_timer)) { spin_unlock_irqrestore(&xhci->lock, flags); return; }