xref: /freebsd/share/man/man4/acpi_video.4 (revision bc96366c864c07ef352edb92017357917c75b36c)
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26.\" $FreeBSD$
27.\"
28.Dd November 8, 2004
29.Dt ACPI_VIDEO 4
30.Os
31.Sh NAME
32.Nm acpi_video
33.Nd ACPI Video Extensions driver
34.Sh SYNOPSIS
35.Cd "device acpi_video"
36.Sh DESCRIPTION
37This driver uses the ACPI Video Extensions to control display switching and
38backlight brightness.
39The availability of the
40.Xr sysctl 8
41variables depends on the functions offered by the host's ACPI implementation.
42.Sh SYSCTL VARIABLES
43The following sysctls are currently implemented,
44where
45.Aq Ar device
46is
47.Va crt , lcd ,
48or
49.Va tv :
50.Bl -tag -width indent
51.It Va hw.acpi.video. Ns Ao Ar device Ac Ns Va .active
52Current state of the output device.
53.It Va hw.acpi.video. Ns Ao Ar device Ac Ns Va .levels
54List of supported brightness levels.
55.It Va hw.acpi.video. Ns Ao Ar device Ac Ns Va .brightness
56Current brightness level of the device.
57.It Va hw.acpi.video. Ns Ao Ar device Ac Ns Va .fullpower
58Preset brightness level to be used in full power mode.
59.It Va hw.acpi.video. Ns Ao Ar device Ac Ns Va .economy
60Preset brightness level to be used in economy mode.
61.El
62.Pp
63Defaults for these variables can be set in
64.Xr sysctl.conf 5 ,
65which is parsed at boot-time.
66.Sh SEE ALSO
67.Xr acpi 4 ,
68.Xr loader.conf 5 ,
69.Xr sysctl.conf 5 ,
70.Xr sysctl 8
71.Sh HISTORY
72The
73.Nm
74driver first appeared in
75.Fx 5.3 .
76.Sh AUTHORS
77.An -nosplit
78The
79.Nm
80driver was written by
81.An Taku YAMAMOTO Aq Mt taku@cent.saitama-u.ac.jp .
82This manual page was written by
83.An Mark Santcroos Aq Mt marks@ripe.net .
84.Sh BUGS
85Some systems only perform output switching via SMM even though they export
86the proper information via ACPI.
87On such systems, the proper hotkeys or OEM driver (for example,
88.Xr acpi_toshiba 4 )
89must be used instead.
90