'\" t
.\"     Title: usb_set_device_state
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
.\"      Date: May 2018
.\"    Manual: USB Core APIs
.\"    Source: Kernel Hackers Manual 3.16.56
.\"  Language: English
.\"
.TH "USB_SET_DEVICE_STATE" "9" "May 2018" "Kernel Hackers Manual 3\&.16\&" "USB Core APIs"
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.SH "NAME"
usb_set_device_state \- change a device\*(Aqs current state (usbcore, hcds)
.SH "SYNOPSIS"
.HP \w'void\ usb_set_device_state('u
.BI "void usb_set_device_state(struct\ usb_device\ *\ " "udev" ", enum\ usb_device_state\ " "new_state" ");"
.SH "ARGUMENTS"
.PP
\fIudev\fR
.RS 4
pointer to device whose state should be changed
.RE
.PP
\fInew_state\fR
.RS 4
new state value to be stored
.RE
.SH "DESCRIPTION"
.PP
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\*(Aqs state must be protected by the device_state_lock spinlock\&.
.PP
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\&.
.PP
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\*(Aqs descendants\*(Aq states are also set to USB_STATE_NOTATTACHED\&.
.SH "COPYRIGHT"
.br