usb_set_device_state(9) centos man page | unix.com

USB_SET_DEVICE_STATE(9) 					   USB Core APIs					   USB_SET_DEVICE_STATE(9)

NAME
       usb_set_device_state - change a device's current state (usbcore, hcds)

SYNOPSIS
       void usb_set_device_state(struct usb_device * udev, enum usb_device_state new_state);

ARGUMENTS
       udev
	   pointer to device whose state should be changed

       new_state
	   new state value to be stored

DESCRIPTION
       udev->state is _not_ fully protected by the device lock. Although most transitions are made only while holding the lock, the state can can
       change to USB_STATE_NOTATTACHED at almost any time. This is so that devices can be marked as disconnected as soon as possible, without
       having to wait for any semaphores to be released. As a result, all changes to any device's state must be protected by the device_state_lock
       spinlock.

       Once a device has been added to the device tree, all changes to its state should be made using this routine. The state should _not_ be set
       directly.

       If udev->state is already USB_STATE_NOTATTACHED then no change is made. Otherwise udev->state is set to new_state, and if new_state is
       USB_STATE_NOTATTACHED then all of udev's descendants' states are also set to USB_STATE_NOTATTACHED.

COPYRIGHT
Kernel Hackers Manual 3.10					     June 2014						   USB_SET_DEVICE_STATE(9)