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How to drive a LCD on ARM based linux System
12-18-2007
How to drive a LCD on ARM based linux System
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ACPI_PANASONIC(4) BSD Kernel Interfaces Manual ACPI_PANASONIC(4) NAME
acpi_panasonic -- ACPI hotkey driver for Panasonic laptops SYNOPSIS
To compile this driver into the kernel, place the following line in your kernel configuration file: device acpi_panasonic Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5): acpi_panasonic_load="YES" DESCRIPTION
The acpi_panasonic driver enables such hotkey facilities of various Panasonic laptops as changing LCD brightness, controlling mixer volumes, entering sleep or suspended state and so on. On the following models it is reported to work: Let's note (or Toughbook, outside Japan) CF- R1N, CF-R2A and CF-R3. It may also work on other models as well. The driver consists of three functionalities. The first is to detect hotkey events and take corresponding actions, which include changing LCD luminance and speaker mute state. The second role is to notify occurrences of the event by way of devctl(4) and eventually to devd(8). The third and last is to provide a way to adjust LCD brightness and sound mute state via sysctl(8). Hotkeys There are 9 hotkeys available on the supported hardware: Fn+F1 Make LCD backlight darker. Fn+F2 Make LCD backlight brighter. Fn+F3 Switch video output between LCD and CRT. Not supported by the acpi_panasonic driver. Fn+F4 Toggle muting the speaker. Fn+F5 Turn the mixer volume down. Fn+F6 Turn the mixer volume up. Fn+F7 Enter suspend-to-RAM state. Fn+F9 Show battery status. Fn+F10 Enter suspend-to-disk state. Actions are automatically taken within the driver for Fn+F1, Fn+F2 and Fn+F4. For the other events such as mixer control and showing battery status, devd(8) should take the role as described below. devd(8) Events When notified to devd(8), the hotkey event provides the following information: system "ACPI" subsystem "Panasonic" type The source of the event in ACPI namespace. The value depends on the model but typically "\_SB_.HKEY". notify Event code (see below). Event codes to be generated are assigned as follows: 0x81-0x86, 0x89 Fn+F<n> pressed. 0x81 corresponds to Fn+F1, 0x82 corresponds to Fn+F2, and so on. 0x01-0x07, 0x09, 0x1a Fn+F<n> released. 0x01 corresponds to Fn+F1, 0x02 corresponds to Fn+F2, and so on. SYSCTL VARIABLES
The following MIBs are available: hw.acpi.panasonic.lcd_brightness_max The maximum level of brightness. The value is read only and automatically set according to hardware model. hw.acpi.panasonic.lcd_brightness_min The minimum level of brightness. The value is read only and automatically set according to hardware model. hw.acpi.panasonic.lcd_brightness Current brightness level of the LCD (read-write). The value ranges from hw.acpi.panasonic.lcd_brightness_min to hw.acpi.panasonic.lcd_brightness_max. hw.acpi.panasonic.sound_mute A read-write boolean flag to control whether to mute the speaker. The value 1 means to mute and 0 not. SEE ALSO
acpi(4), devd.conf(5), devd(8), sysctl(8) HISTORY
The acpi_panasonic driver first appeared in FreeBSD 5.3. AUTHORS
The acpi_panasonic driver and this manual page were written by OGAWA Takaya <t-ogawa@triaez.kaisei.org> and TAKAHASHI Yoshihiro <nyan@FreeBSD.org>. BSD
February 25, 2012 BSD