usb_reset_configuration(9) [centos man page]

USB_RESET_CONFIGURAT(9) 					   USB Core APIs					   USB_RESET_CONFIGURAT(9)

NAME

       usb_reset_configuration - lightweight device reset

SYNOPSIS

       int usb_reset_configuration(struct usb_device * dev);

ARGUMENTS

       dev
	   the device whose configuration is being reset

DESCRIPTION

       This issues a standard SET_CONFIGURATION request to the device using the current configuration. The effect is to reset most USB-related
       state in the device, including interface altsettings (reset to zero), endpoint halts (cleared), and endpoint state (only for bulk and
       interrupt endpoints). Other usbcore state is unchanged, including bindings of usb device drivers to interfaces.

       Because this affects multiple interfaces, avoid using this with composite (multi-interface) devices. Instead, the driver for each interface
       may use usb_set_interface on the interfaces it claims. Be careful though; some devices don't support the SET_INTERFACE request, and others
       won't reset all the interface state (notably endpoint state). Resetting the whole configuration would affect other drivers' interfaces.

       The caller must own the device lock.

RETURN

       Zero on success, else a negative error code.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						   USB_RESET_CONFIGURAT(9)

USB_SET_INTERFACE(9)						   USB Core APIs					      USB_SET_INTERFACE(9)

NAME

       usb_set_interface - Makes a particular alternate setting be current

SYNOPSIS

       int usb_set_interface(struct usb_device * dev, int interface, int alternate);

ARGUMENTS

       dev
	   the device whose interface is being updated

       interface
	   the interface being updated

       alternate
	   the setting being chosen.

CONTEXT

       !in_interrupt ()

DESCRIPTION

       This is used to enable data transfers on interfaces that may not be enabled by default. Not all devices support such configurability. Only
       the driver bound to an interface may change its setting.

       Within any given configuration, each interface may have several alternative settings. These are often used to control levels of bandwidth
       consumption. For example, the default setting for a high speed interrupt endpoint may not send more than 64 bytes per microframe, while
       interrupt transfers of up to 3KBytes per microframe are legal. Also, isochronous endpoints may never be part of an interface's default
       setting. To access such bandwidth, alternate interface settings must be made current.

       Note that in the Linux USB subsystem, bandwidth associated with an endpoint in a given alternate setting is not reserved until an URB is
       submitted that needs that bandwidth. Some other operating systems allocate bandwidth early, when a configuration is chosen.

       This call is synchronous, and may not be used in an interrupt context. Also, drivers must not change altsettings while urbs are scheduled
       for endpoints in that interface; all such urbs must first be completed (perhaps forced by unlinking).

       Returns zero on success, or else the status code returned by the underlying usb_control_msg call.

COPYRIGHT

Kernel Hackers Manual 2.6.					     July 2010						      USB_SET_INTERFACE(9)