Man page 9 : usb_interrupt_msg

usb_interrupt_msg - Builds an interrupt urb, sends it off and waits for completion

int usb_interrupt_msg(struct usb_device *  usb_dev , unsigned int  pipe , void *  data , int  len , int *  actual_length , int  timeout );

usb_dev
    pointer to the usb device to send the message to

pipe
    endpoint « pipe » to send the message to

data
    pointer to the data to send

len
    length in bytes of the data to send

actual_length
    pointer to a location to put the actual length transferred in bytes

timeout
    time in msecs to wait for the message to complete before timing out (if 0 the wait is forever)

!in_interrupt ()

This function sends a simple interrupt message to a specified endpoint and waits for the message to complete, or timeout.

If successful, it returns 0, otherwise a negative error number. The number of actual bytes transferred will be stored in the actual_length paramater.

DonAqt use this function from within an interrupt context, like a bottom half handler. If you need an asynchronous message, or need to send a message from within interrupt context, use usb_submit_urb If a thread in your driver uses this call, make sure your disconnect method can wait for it to complete. Since you donAqt have a handle on the URB used, you canAqt cancel the request.