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- jessie 3.16.56-1+deb8u1
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¶
udevpointer 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¶
May 2018 | Kernel Hackers Manual 3.16 |