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usb_control_msg(9) [suse man page]

USB_CONTROL_MSG(9)						   USB Core APIs						USB_CONTROL_MSG(9)

NAME

       usb_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.

COPYRIGHT

Kernel Hackers Manual 2.6.					     July 2010							USB_CONTROL_MSG(9)

Check Out this Related Man Page

USB_SG_INIT(9)							   USB Core APIs						    USB_SG_INIT(9)

NAME

       usb_sg_init - initializes scatterlist-based bulk/interrupt I/O request

SYNOPSIS

       int usb_sg_init(struct usb_sg_request * io, struct usb_device * dev, unsigned pipe, unsigned period, struct scatterlist * sg, int nents,
		       size_t length, gfp_t mem_flags);

ARGUMENTS

       io
	   request block being initialized. until usb_sg_wait returns, treat this as a pointer to an opaque block of memory,

       dev
	   the usb device that will send or receive the data

       pipe
	   endpoint "pipe" used to transfer the data

       period
	   polling rate for interrupt endpoints, in frames or (for high speed endpoints) microframes; ignored for bulk

       sg
	   scatterlist entries

       nents
	   how many entries in the scatterlist

       length
	   how many bytes to send from the scatterlist, or zero to send every byte identified in the list.

       mem_flags
	   SLAB_* flags affecting memory allocations in this call

DESCRIPTION

       Returns zero for success, else a negative errno value. This initializes a scatter/gather request, allocating resources such as I/O mappings
       and urb memory (except maybe memory used by USB controller drivers).

       The request must be issued using usb_sg_wait, which waits for the I/O to complete (or to be canceled) and then cleans up all resources
       allocated by usb_sg_init.

       The request may be canceled with usb_sg_cancel, either before or after usb_sg_wait is called.

COPYRIGHT

Kernel Hackers Manual 2.6.					     July 2010							    USB_SG_INIT(9)
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