releases/upstream/2.6.23-rc1/0008-ACPI-thinkpad-acpi-update-CMOS-commands-documentat.patch

   1 From d54b7d7f8026300c612dd733d501fcbc22fd0370 Mon Sep 17 00:00:00 2001
   2 From: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
   3 Date: Wed, 18 Jul 2007 23:45:33 -0300
   4 Subject: ACPI: thinkpad-acpi: update CMOS commands documentation
   5
   6 The CMOS set of commands is often just used to keep the CMOS NVRAM in sync
   7 with whatever the ACPI BIOS has been doing in modern ThinkPads.  In older
   8 ThinkPads, it actually carried out real actions.  Document this.
   9
  10 Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
  11 Signed-off-by: Len Brown <len.brown@intel.com>
  12 ---
  13  Documentation/thinkpad-acpi.txt |   35 +++++++++++++++++++++--------------
  14  1 files changed, 21 insertions(+), 14 deletions(-)
  15
  16 diff --git a/Documentation/thinkpad-acpi.txt b/Documentation/thinkpad-acpi.txt
  17 index 7a06a27..bd00d14 100644
  18 --- a/Documentation/thinkpad-acpi.txt
  19 +++ b/Documentation/thinkpad-acpi.txt
  20 @@ -464,27 +464,34 @@ CMOS control
  21  procfs: /proc/acpi/ibm/cmos
  22  sysfs device attribute: cmos_command
  23
  24 -This feature is used internally by the ACPI firmware to control the
  25 -ThinkLight on most newer ThinkPad models. It may also control LCD
  26 -brightness, sounds volume and more, but only on some models.
  27 +This feature is mostly used internally by the ACPI firmware to keep the legacy
  28 +CMOS NVRAM bits in sync with the current machine state, and to record this
  29 +state so that the ThinkPad will retain such settings across reboots.
  30 +
  31 +Some of these commands actually perform actions in some ThinkPad models, but
  32 +this is expected to disappear more and more in newer models.  As an example, in
  33 +a T43 and in a X40, commands 12 and 13 still control the ThinkLight state for
  34 +real, but commands 0 to 2 don't control the mixer anymore (they have been
  35 +phased out) and just update the NVRAM.
  36
  37  The range of valid cmos command numbers is 0 to 21, but not all have an
  38  effect and the behavior varies from model to model.  Here is the behavior
  39  on the X40 (tpb is the ThinkPad Buttons utility):
  40
  41 -       0 - no effect but tpb reports "Volume down"
  42 -       1 - no effect but tpb reports "Volume up"
  43 -       2 - no effect but tpb reports "Mute on"
  44 -       3 - simulate pressing the "Access IBM" button
  45 -       4 - LCD brightness up
  46 -       5 - LCD brightness down
  47 -       11 - toggle screen expansion
  48 -       12 - ThinkLight on
  49 -       13 - ThinkLight off
  50 -       14 - no effect but tpb reports ThinkLight status change
  51 +       0 - Related to "Volume down" key press
  52 +       1 - Related to "Volume up" key press
  53 +       2 - Related to "Mute on" key press
  54 +       3 - Related to "Access IBM" key press
  55 +       4 - Related to "LCD brightness up" key pess
  56 +       5 - Related to "LCD brightness down" key press
  57 +       11 - Related to "toggle screen expansion" key press/function
  58 +       12 - Related to "ThinkLight on"
  59 +       13 - Related to "ThinkLight off"
  60 +       14 - Related to "ThinkLight" key press (toggle thinklight)
  61
  62  The cmos command interface is prone to firmware split-brain problems, as
  63 -in newer ThinkPads it is just a compatibility layer.
  64 +in newer ThinkPads it is just a compatibility layer.  Do not use it, it is
  65 +exported just as a debug tool.
  66
  67  LED control -- /proc/acpi/ibm/led
  68  ---------------------------------
  69 --
  70 1.5.2.1
  71