Acer Laptop WMI Extras Driver
  http://code.google.com/p/aceracpi

  Version 0.3
  4th April 2009

  Copyright 2007-2009 Carlos Corbacho <carlos@strangeworlds.co.uk>

  
  acer-wmi is a driver to allow you to control various parts of your Acer laptop
  hardware under Linux which are exposed via ACPI-WMI.
  
  This driver completely replaces the old out-of-tree acer_acpi, which I am
  currently maintaining for bug fixes only on pre-2.6.25 kernels. All development
  work is now focused solely on acer-wmi.
  
  Disclaimer
  **********
  
  Acer and Wistron have provided nothing towards the development acer_acpi or
  acer-wmi. All information we have has been through the efforts of the developers
  and the users to discover as much as possible about the hardware.
  
  As such, I do warn that this could break your hardware - this is extremely
  unlikely of course, but please bear this in mind.
  
  Background
  **********
  
  acer-wmi is derived from acer_acpi, originally developed by Mark
  Smith in 2005, then taken over by Carlos Corbacho in 2007, in order to activate
  the wireless LAN card under a 64-bit version of Linux, as acerhk[1] (the
  previous solution to the problem) relied on making 32 bit BIOS calls which are
  not possible in kernel space from a 64 bit OS.
  
  [1] acerhk: http://www.cakey.de/acerhk/
  
  Supported Hardware
  ******************

  NOTE: The Acer Aspire One is not supported hardware. It cannot work with
  acer-wmi until Acer fix their ACPI-WMI implementation on them, so has been
  blacklisted until that happens.

  Please see the website for the current list of known working hardware:

  
  http://code.google.com/p/aceracpi/wiki/SupportedHardware
  
  If your laptop is not listed, or listed as unknown, and works with acer-wmi,
  please contact me with a copy of the DSDT.
  
  If your Acer laptop doesn't work with acer-wmi, I would also like to see the
  DSDT.
  
  To send me the DSDT, as root/sudo:

  cat /sys/firmware/acpi/tables/DSDT > dsdt

  
  And send me the resulting 'dsdt' file.
  
  Usage
  *****
  
  On Acer laptops, acer-wmi should already be autoloaded based on DMI matching.
  For non-Acer laptops, until WMI based autoloading support is added, you will
  need to manually load acer-wmi.
  
  acer-wmi creates /sys/devices/platform/acer-wmi, and fills it with various
  files whose usage is detailed below, which enables you to control some of the
  following (varies between models):
  
  * the wireless LAN card radio
  * inbuilt Bluetooth adapter
  * inbuilt 3G card
  * mail LED of your laptop
  * brightness of the LCD panel
  
  Wireless
  ********
  
  With regards to wireless, all acer-wmi does is enable the radio on the card. It
  is not responsible for the wireless LED - once the radio is enabled, this is
  down to the wireless driver for your card. So the behaviour of the wireless LED,
  once you enable the radio, will depend on your hardware and driver combination.
  
  e.g. With the BCM4318 on the Acer Aspire 5020 series:
  
  ndiswrapper: Light blinks on when transmitting

  b43: Solid light, blinks off when transmitting

  
  Wireless radio control is unconditionally enabled - all Acer laptops that support
  acer-wmi come with built-in wireless. However, should you feel so inclined to
  ever wish to remove the card, or swap it out at some point, please get in touch
  with me, as we may well be able to gain some data on wireless card detection.

  The wireless radio is exposed through rfkill.

  
  Bluetooth
  *********
  
  For bluetooth, this is an internal USB dongle, so once enabled, you will get
  a USB device connection event, and a new USB device appears. When you disable
  bluetooth, you get the reverse - a USB device disconnect event, followed by the
  device disappearing again.
  
  Bluetooth is autodetected by acer-wmi, so if you do not have a bluetooth module
  installed in your laptop, this file won't exist (please be aware that it is
  quite common for Acer not to fit bluetooth to their laptops - so just because
  you have a bluetooth button on the laptop, doesn't mean that bluetooth is
  installed).
  
  For the adventurously minded - if you want to buy an internal bluetooth
  module off the internet that is compatible with your laptop and fit it, then
  it will work just fine with acer-wmi.

  Bluetooth is exposed through rfkill.

  
  3G
  **
  
  3G is currently not autodetected, so the 'threeg' file is always created under
  sysfs. So far, no-one in possession of an Acer laptop with 3G built-in appears to
  have tried Linux, or reported back, so we don't have any information on this.
  
  If you have an Acer laptop that does have a 3G card in, please contact me so we
  can properly detect these, and find out a bit more about them.
  
  To read the status of the 3G card (0=off, 1=on):
  cat /sys/devices/platform/acer-wmi/threeg
  
  To enable the 3G card:
  echo 1 > /sys/devices/platform/acer-wmi/threeg
  
  To disable the 3G card:
  echo 0 > /sys/devices/platform/acer-wmi/threeg
  
  To set the state of the 3G card when loading acer-wmi, pass:
  threeg=X (where X is 0 or 1)
  
  Mail LED
  ********
  
  This can be found in most older Acer laptops supported by acer-wmi, and many
  newer ones - it is built into the 'mail' button, and blinks when active.
  
  On newer (WMID) laptops though, we have no way of detecting the mail LED. If
  your laptop identifies itself in dmesg as a WMID model, then please try loading
  acer_acpi with:
  
  force_series=2490
  
  This will use a known alternative method of reading/ writing the mail LED. If
  it works, please report back to me with the DMI data from your laptop so this
  can be added to acer-wmi.
  
  The LED is exposed through the LED subsystem, and can be found in:

  /sys/devices/platform/acer-wmi/leds/acer-wmi::mail/

  
  The mail LED is autodetected, so if you don't have one, the LED device won't
  be registered.

  Backlight
  *********
  
  The backlight brightness control is available on all acer-wmi supported
  hardware. The maximum brightness level is usually 15, but on some newer laptops
  it's 10 (this is again autodetected).
  
  The backlight is exposed through the backlight subsystem, and can be found in:
  
  /sys/devices/platform/acer-wmi/backlight/acer-wmi/
  
  Credits
  *******
  
  Olaf Tauber, who did the real hard work when he developed acerhk

  http://www.cakey.de/acerhk/

  All the authors of laptop ACPI modules in the kernel, whose work
  was an inspiration in the early days of acer_acpi
  Mathieu Segaud, who solved the problem with having to modprobe the driver
  twice in acer_acpi 0.2.
  Jim Ramsay, who added support for the WMID interface
  Mark Smith, who started the original acer_acpi
  
  And the many people who have used both acer_acpi and acer-wmi.