| usb_set_device_state(9) - phpMan
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 4.8. January 2017 USB_SET_DEVICE_STATE(9)
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