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usb_control_msg(9) [centos 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. 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, the number of bytes transferred. Otherwise, a negative error number. COPYRIGHT
Kernel Hackers Manual 3.10 June 2014 USB_CONTROL_MSG(9)

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USB_BULK_MSG(9) 						   USB Core APIs						   USB_BULK_MSG(9)

NAME
usb_bulk_msg - Builds a bulk urb, sends it off and waits for completion SYNOPSIS
int usb_bulk_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 bulk 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. Because there is no usb_interrupt_msg and no USBDEVFS_INTERRUPT ioctl, users are forced to abuse this routine by using it to submit URBs for interrupt endpoints. We will take the liberty of creating an interrupt URB (with the default interval) if the target is an interrupt endpoint. RETURN
If successful, 0. Otherwise a negative error number. The number of actual bytes transferred will be stored in the actual_length paramater. COPYRIGHT
Kernel Hackers Manual 3.10 June 2014 USB_BULK_MSG(9)
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