usb_interrupt_msg (9) Linux Manual Page
usb_interrupt_msg – Builds an interrupt urb, sends it off and waits for completion
Synopsis
int usb_interrupt_msg(struct usb_device *usb_dev, unsigned int pipe, void *data, int len, int *actual_length, int timeout);Arguments
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)
Context
!in_interrupt ()
Description
This function sends a simple interrupt message to a specified endpoint and waits for the message to complete, or timeout.
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.
Return
If successful, 0. Otherwise a negative error number. The number of actual bytes transferred will be stored in the actual_length parameter.