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

6       usb_bulk_msg - Builds a bulk urb, sends it off and waits for completion
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SYNOPSIS

9       int usb_bulk_msg(struct usb_device * usb_dev, unsigned int pipe,
10                        void * data, int len, int * actual_length,
11                        int timeout);
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ARGUMENTS

14       usb_dev
15           pointer to the usb device to send the message to
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17       pipe
18           endpoint “pipe” to send the message to
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20       data
21           pointer to the data to send
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23       len
24           length in bytes of the data to send
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26       actual_length
27           pointer to a location to put the actual length transferred in bytes
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29       timeout
30           time in msecs to wait for the message to complete before timing out
31           (if 0 the wait is forever)
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CONTEXT

34       !in_interrupt ()
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DESCRIPTION

37       This function sends a simple bulk message to a specified endpoint and
38       waits for the message to complete, or timeout.
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40       If successful, it returns 0, otherwise a negative error number. The
41       number of actual bytes transferred will be stored in the actual_length
42       paramater.
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44       Don´t use this function from within an interrupt context, like a bottom
45       half handler. If you need an asynchronous message, or need to send a
46       message from within interrupt context, use usb_submit_urb If a thread
47       in your driver uses this call, make sure your disconnect method can
48       wait for it to complete. Since you don´t have a handle on the URB used,
49       you can´t cancel the request.
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51       Because there is no usb_interrupt_msg and no USBDEVFS_INTERRUPT ioctl,
52       users are forced to abuse this routine by using it to submit URBs for
53       interrupt endpoints. We will take the liberty of creating an interrupt
54       URB (with the default interval) if the target is an interrupt endpoint.
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57Kernel Hackers Manual 2.6.         June 2019                   USB_BULK_MSG(9)
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