usb_interrupt_msg
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Name

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.

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

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.

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