File:  [DragonFly] / src / share / man / man9 / device_get_state.9
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    1: .\" -*- nroff -*-
    2: .\"
    3: .\" Copyright (c) 1998 Doug Rabson
    4: .\"
    5: .\" All rights reserved.
    6: .\"
    7: .\" This program is free software.
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    9: .\" Redistribution and use in source and binary forms, with or without
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   29: .\" $FreeBSD: src/share/man/man9/device_get_state.9,v 1.3.2.5 2001/12/17 11:30:18 ru Exp $
   30: .\" $DragonFly: src/share/man/man9/device_get_state.9,v 1.2 2003/06/17 04:37:01 dillon Exp $
   31: .\"
   32: .Dd June 16, 1998
   33: .Dt DEVICE_GET_STATE 9
   34: .Os
   35: .Sh NAME
   36: .Nm device_get_state ,
   37: .Nm device_busy ,
   38: .Nm device_unbusy ,
   39: .Nm device_is_alive
   40: .Nd manipulate device state
   41: .Sh SYNOPSIS
   42: .In sys/param.h
   43: .In sys/bus.h
   44: .Ft device_state_t
   45: .Fn device_get_state "device_t dev"
   46: .Ft void
   47: .Fn device_busy "device_t dev"
   48: .Ft void
   49: .Fn device_unbusy "device_t dev"
   50: .Ft int
   51: .Fn device_is_alive "device_t dev"
   52: .Sh DESCRIPTION
   53: The current state of a device is accessed by calling
   54: .Xr device_get_state 9
   55: which returns
   56: .Dv DS_NOTPRESENT ,
   57: .Dv DS_ALIVE ,
   58: .Dv DS_ATTACHED
   59: or
   60: .Dv DS_BUSY
   61: (described in
   62: .Xr device 9 ) .
   63: To test see if a device was successfully probed, call
   64: .Xr device_is_alive 9
   65: which simply returns if the state is greater or equal to
   66: .Dv DS_ALIVE .
   67: .Pp
   68: Each device has a busy count which is incremented when
   69: .Xr device_busy 9
   70: is called and decremented when
   71: .Xr device_unbusy 9
   72: is called.  Both routines return an error if the device state is less
   73: than
   74: .Dv DS_ATTACHED .
   75: .Pp
   76: When
   77: .Xr device_busy 9
   78: is called on a device in the
   79: .Dv DS_ATTACHED
   80: state, the device changes to the
   81: .Dv DS_BUSY
   82: state.
   83: When
   84: .Xr device_unbusy 9
   85: is called and after decrementing, the busy count for the device is
   86: zero, the device changes to the
   87: .Dv DS_ATTACHED
   88: state.
   89: .Sh SEE ALSO
   90: .Xr device 9
   91: .Sh AUTHORS
   92: This man page was written by
   93: .An Doug Rabson .