xref: /freebsd/share/man/man4/acpi_video.4 (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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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 COMPATIBILITY
67In order for
68.Nm
69to attach correctly,
70.Nm
71should be loaded after any of the DRM kernel modules.
72This can be achieved by setting the correct order in
73.Xr rc.conf 5
74using the kld_list directive.
75.Sh SEE ALSO
76.Xr acpi 4 ,
77.Xr loader.conf 5 ,
78.Xr sysctl.conf 5 ,
79.Xr sysctl 8
80.Sh HISTORY
81The
82.Nm
83driver first appeared in
84.Fx 5.3 .
85.Sh AUTHORS
86.An -nosplit
87The
88.Nm
89driver was written by
90.An Taku YAMAMOTO Aq Mt taku@cent.saitama-u.ac.jp .
91This manual page was written by
92.An Mark Santcroos Aq Mt marks@ripe.net .
93.Sh BUGS
94Some systems only perform output switching via SMM even though they export
95the proper information via ACPI.
96On such systems, the proper hotkeys or OEM driver (for example,
97.Xr acpi_toshiba 4 )
98must be used instead.
99