Provided by: linux-doc-2.6.15_2.6.15-23.39_all bug


       usb_control_msg  -  Builds  a  control  urb, sends it off and waits for


       int usb_control_msg  (struct usb_device * dev, unsigned int pipe,
                              __u8 request, __u8 requesttype, __u16 value,
                              __u16 index, void * data, __u16 size,
                              int timeout);


       dev    pointer to the usb device to send the message to

       pipe   endpoint ‘‘pipe’’ to send the message to

              USB message request value

              USB message request type value

       value  USB message value

       index  USB message index value

       data   pointer to the data to send

       size   length in bytes of the data to send

              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 control message to  a  specified  endpoint
       and waits for the message to complete, or timeout.

       If  successful, it returns the number of bytes transferred, otherwise a
       negative error number.

       Don’t 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 don’t have a handle on the URB used,
       you can’t cancel the request.