USB_CONTROL_MSG(9) USB Core APIs USB_CONTROL_MSG(9)NAMEusb_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 in msecs to wait for the message to complete before timing out
(if 0 the wait is forever)
CONTEXT
!in_interrupt ()
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 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.
COPYRIGHTKernel Hackers Manual 2.6. November 2013 USB_CONTROL_MSG(9)
