1USB_SET_DEVICE_STATE(9)          USB Core APIs         USB_SET_DEVICE_STATE(9)
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NAME

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

9       void usb_set_device_state(struct usb_device * udev,
10                                 enum usb_device_state new_state);
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ARGUMENTS

13       udev
14           pointer to device whose state should be changed
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16       new_state
17           new state value to be stored
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DESCRIPTION

20       udev->state is _not_ fully protected by the device lock. Although most
21       transitions are made only while holding the lock, the state can can
22       change to USB_STATE_NOTATTACHED at almost any time. This is so that
23       devices can be marked as disconnected as soon as possible, without
24       having to wait for any semaphores to be released. As a result, all
25       changes to any device's state must be protected by the
26       device_state_lock spinlock.
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28       Once a device has been added to the device tree, all changes to its
29       state should be made using this routine. The state should _not_ be set
30       directly.
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32       If udev->state is already USB_STATE_NOTATTACHED then no change is made.
33       Otherwise udev->state is set to new_state, and if new_state is
34       USB_STATE_NOTATTACHED then all of udev's descendants' states are also
35       set to USB_STATE_NOTATTACHED.
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38Kernel Hackers Manual 3.10         June 2019           USB_SET_DEVICE_STATE(9)
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