Compatibility Wrappers

The USB core contains a number of higher level functions which were introduced as compatibility wrappers for the older APIs. Some of these functions can still be used to issue blocking control or bulk transfers.

• 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);

  Issues a blocking standard control request. The arguments are according to [4] section 9.3. A timeout in jiffies has to be specified. If successful the return value is a positive number which represents the bytes transferred otherwise an error code is returned.

• int usb_bulk_msg(struct usb_device *usb_dev, unsigned int pipe, void *data, int len, unsigned long *actual_length, int timeout);

  Issues a blocking bulk transfer. The standard arguments should be self explaining. actual_length is an optional pointer to a variable which carries the actual number of bytes transferred by this request. A timeout in jiffies has to be specified.