While output urb's snd_complete_urb() is executing, calling prepare_outbound_urb() may cause endpoint stopped before prepare_outbound_urb() returns and result in next urb submitted to stopped endpoint. usb-audio driver cannot re-use it afterwards as the urb is still hold by usb stack.
This change checks EP_FLAG_RUNNING flag after prepare_outbound_urb() again to let snd_complete_urb() know the endpoint already stopped and does not submit next urb. Below kind of error will be fixed:
[ 213.153103] usb 1-2: timeout: still 1 active urbs on EP #1 [ 213.164121] usb 1-2: cannot submit urb 0, error -16: unknown error
Signed-off-by: Henry Lin henryl@nvidia.com --- sound/usb/endpoint.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/sound/usb/endpoint.c b/sound/usb/endpoint.c index a2ab8e8d3a93..4a9a2f6ef5a4 100644 --- a/sound/usb/endpoint.c +++ b/sound/usb/endpoint.c @@ -388,6 +388,9 @@ static void snd_complete_urb(struct urb *urb) }
prepare_outbound_urb(ep, ctx); + /* can be stopped during prepare callback */ + if (unlikely(!test_bit(EP_FLAG_RUNNING, &ep->flags))) + goto exit_clear; } else { retire_inbound_urb(ep, ctx); /* can be stopped during retire callback */