[alsa-devel] question about webcam audio capture

hi all: I try to do webcam audio capture on my arm platform. when I execute audio capture I got below message "retire_capture_urb: 108 callbacks suppressed"

my questions: 1. where I can get the message "retire_capture_urb: 108 callbacks suppressed" show in sound/usb driver? I try to grep -rwn '"retire_capture_urb.*' sound/usb/*, but get nothing.

2. from usb mon log, it seems HW keep Active status high even until ehci_io_watchdog happen, because the ep status is -EXDEV. if my observation is correct, is it possible to modify usb sound driver to purposely send fix number urbs. Because from the usb mon log, the first 8 urb will get time out already.

thanks for your help in advance,