ACPI Video Extensions driver
This driver uses the ACPI Video Extensions to control display switching and
backlight brightness. The availability of the sysctl(8)
variables depends on the functions offered by the host's ACPI implementation.
The following sysctls are currently implemented, where
⟨device⟩ is crt,
lcd, or tv:
- Current state of the output device.
- List of supported brightness levels.
- Current brightness level of the device.
- Preset brightness level to be used in full power mode.
- Preset brightness level to be used in economy mode.
Defaults for these variables can be set in
sysctl.conf(5), which is parsed at boot-time.
acpi_video driver first appeared in
Some systems only perform output switching via SMM even though they export the
proper information via ACPI. On such systems, the proper hotkeys or OEM driver
(for example, acpi_toshiba(4)) must be used instead.