Does anyone know anything about ACPI key-based laptop backlight control?My "white-box" laptop is apparently based on an Asus mainboard. dmidecode says:
Handle 0x0001, DMI type 1, 25 bytes. System InformationManufacturer: ASUSTeK Computer Inc. Product Name: M7V Version: 1.0 Serial Number: SSN12345678901234567
UUID: 28CE5D8A-0000-0080-385D-0017312C16F2
Wake-up Type: Power Switch
Love that serial number.
Anyway, this hardware apparently has an ambient light sensor, and three ACPI
keys. In Win XP, the first key controls the backlight automatic/manual mode.
In automatic mode, the ambient light sensor gradually reduces the backlight,
based on the room light level, in small incremental steps, from about 100%
brightness to about 30%. In manual mode, the sensor itself is disabled and
the other two ACPI keys incrementally step up or step down the backlight
power. Win XP responds to the ACPI keys with small popup indicators.
GRUB's menu comes up with the light sensor in manual mode. As soon as the kernel boots, it goes to automatic, and there is no further response to any of these three ACPI keys. Booting with "noacpi" keeps the light sensor in manual mode.
In neither case can I, apparently, switch between manual and automatic mode with the ACPI keys. Except for this, I have ACPI working fine. I have other ACPI keys that enable/disable the external VGA port, and they work as advertised.
My normal light level appears to be right at the upper sensor range, and the nearly-subliminal back-and-forth backlight light level adjustment becomes irritating rather quickly. But there's no response to these three ACPI keys, nothing in syslog, and the backlight settings in Gnome's power management do nothing.
There's nothing else in dmidecode's output, or lspci's output, that refers to the sensor.
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