xref: /freebsd/share/man/man4/acpi_video.4 (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
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26.Dd November 8, 2004
27.Dt ACPI_VIDEO 4
28.Os
29.Sh NAME
30.Nm acpi_video
31.Nd ACPI Video Extensions driver
32.Sh SYNOPSIS
33.Cd "device acpi_video"
34.Sh DESCRIPTION
35This driver uses the ACPI Video Extensions to control display switching and
36backlight brightness.
37The availability of the
38.Xr sysctl 8
39variables depends on the functions offered by the host's ACPI implementation.
40.Sh SYSCTL VARIABLES
41The following sysctls are currently implemented,
42where
43.Aq Ar device
44is
45.Va crt , lcd ,
46or
47.Va tv :
48.Bl -tag -width indent
49.It Va hw.acpi.video. Ns Ao Ar device Ac Ns Va .active
50Current state of the output device.
51.It Va hw.acpi.video. Ns Ao Ar device Ac Ns Va .levels
52List of supported brightness levels.
53.It Va hw.acpi.video. Ns Ao Ar device Ac Ns Va .brightness
54Current brightness level of the device.
55.It Va hw.acpi.video. Ns Ao Ar device Ac Ns Va .fullpower
56Preset brightness level to be used in full power mode.
57.It Va hw.acpi.video. Ns Ao Ar device Ac Ns Va .economy
58Preset brightness level to be used in economy mode.
59.El
60.Pp
61Defaults for these variables can be set in
62.Xr sysctl.conf 5 ,
63which is parsed at boot-time.
64.Sh COMPATIBILITY
65In order for
66.Nm
67to attach correctly,
68.Nm
69should be loaded after any of the DRM kernel modules.
70This can be achieved by setting the correct order in
71.Xr rc.conf 5
72using the kld_list directive.
73.Sh SEE ALSO
74.Xr acpi 4 ,
75.Xr loader.conf 5 ,
76.Xr sysctl.conf 5 ,
77.Xr sysctl 8
78.Sh HISTORY
79The
80.Nm
81driver first appeared in
82.Fx 5.3 .
83.Sh AUTHORS
84.An -nosplit
85The
86.Nm
87driver was written by
88.An Taku YAMAMOTO Aq Mt taku@cent.saitama-u.ac.jp .
89This manual page was written by
90.An Mark Santcroos Aq Mt marks@ripe.net .
91.Sh BUGS
92Some systems only perform output switching via SMM even though they export
93the proper information via ACPI.
94On such systems, the proper hotkeys or OEM driver (for example,
95.Xr acpi_toshiba 4 )
96must be used instead.
97