1USB_CONTROL_MSG(9)               USB Core APIs              USB_CONTROL_MSG(9)
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NAME

6       usb_control_msg - Builds a control urb, sends it off and waits for
7       completion
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SYNOPSIS

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

15       dev
16           pointer to the usb device to send the message to
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18       pipe
19           endpoint “pipe” to send the message to
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21       request
22           USB message request value
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24       requesttype
25           USB message request type value
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27       value
28           USB message value
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30       index
31           USB message index value
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33       data
34           pointer to the data to send
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36       size
37           length in bytes of the data to send
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39       timeout
40           time in msecs to wait for the message to complete before timing out
41           (if 0 the wait is forever)
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CONTEXT

44       !in_interrupt ()
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DESCRIPTION

47       This function sends a simple control message to a specified endpoint
48       and waits for the message to complete, or timeout.
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50       Don't use this function from within an interrupt context. If you need
51       an asynchronous message, or need to send a message from within
52       interrupt context, use usb_submit_urb. If a thread in your driver uses
53       this call, make sure your disconnect method can wait for it to
54       complete. Since you don't have a handle on the URB used, you can't
55       cancel the request.
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RETURN

58       If successful, the number of bytes transferred. Otherwise, a negative
59       error number.
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62Kernel Hackers Manual 3.10         June 2019                USB_CONTROL_MSG(9)
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