Provided by:
kernel-doc-2.4.27_2.4.27-12_all 
NAME
usb_control_msg - Builds a control urb, sends it off and waits for
completion
SYNOPSIS
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);
ARGUMENTS
dev pointer to the usb device to send the message to
pipe endpoint "pipe" to send the message to
request USB message request value
requesttype 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
timeout time to wait for the message to complete before timing out
(if 0 the wait is forever)
DESCRIPTION
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,
it returns a negative error number.
Don’t use this function from within an interrupt context, like a bottom
half handler. If you need a asyncronous message, or need to send a
message from within interrupt context, use usb_submit_urb