linux/Documentation/laptops/sony-laptop.txt
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   1Sony Notebook Control Driver (SNC) Readme
   2-----------------------------------------
   3        Copyright (C) 2004- 2005 Stelian Pop <stelian@popies.net>
   4        Copyright (C) 2007 Mattia Dongili <malattia@linux.it>
   5
   6This mini-driver drives the SNC and SPIC device present in the ACPI BIOS of the
   7Sony Vaio laptops. This driver mixes both devices functions under the same
   8(hopefully consistent) interface. This also means that the sonypi driver is
   9obsoleted by sony-laptop now.
  10
  11Fn keys (hotkeys):
  12------------------
  13Some models report hotkeys through the SNC or SPIC devices, such events are
  14reported both through the ACPI subsystem as acpi events and through the INPUT
  15subsystem. See the logs of acpid or /proc/acpi/event and
  16/proc/bus/input/devices to find out what those events are and which input
  17devices are created by the driver. Additionally, loading the driver with the
  18debug option will report all events in the kernel log.
  19
  20The "scancodes" passed to the input system (that can be remapped with udev)
  21are indexes to the table "sony_laptop_input_keycode_map" in the sony-laptop.c
  22module.  For example the "FN/E" key combination (EJECTCD on some models)
  23generates the scancode 20 (0x14).
  24
  25Backlight control:
  26------------------
  27If your laptop model supports it, you will find sysfs files in the
  28/sys/class/backlight/sony/
  29directory. You will be able to query and set the current screen
  30brightness:
  31        brightness              get/set screen brightness (an integer
  32                                between 0 and 7)
  33        actual_brightness       reading from this file will query the HW
  34                                to get real brightness value
  35        max_brightness          the maximum brightness value
  36
  37
  38Platform specific:
  39------------------
  40Loading the sony-laptop module will create a
  41/sys/devices/platform/sony-laptop/
  42directory populated with some files.
  43
  44You then read/write integer values from/to those files by using
  45standard UNIX tools.
  46
  47The files are:
  48        brightness_default      screen brightness which will be set
  49                                when the laptop will be rebooted
  50        cdpower                 power on/off the internal CD drive
  51        audiopower              power on/off the internal sound card
  52        lanpower                power on/off the internal ethernet card
  53                                (only in debug mode)
  54        bluetoothpower          power on/off the internal bluetooth device
  55        fanspeed                get/set the fan speed
  56
  57Note that some files may be missing if they are not supported
  58by your particular laptop model.
  59
  60Example usage:
  61        # echo "1" > /sys/devices/platform/sony-laptop/brightness_default
  62sets the lowest screen brightness for the next and later reboots,
  63        # echo "8" > /sys/devices/platform/sony-laptop/brightness_default
  64sets the highest screen brightness for the next and later reboots,
  65        # cat /sys/devices/platform/sony-laptop/brightness_default
  66retrieves the value.
  67
  68        # echo "0" > /sys/devices/platform/sony-laptop/audiopower
  69powers off the sound card,
  70        # echo "1" > /sys/devices/platform/sony-laptop/audiopower
  71powers on the sound card.
  72
  73
  74RFkill control:
  75---------------
  76More recent Vaio models expose a consistent set of ACPI methods to
  77control radio frequency emitting devices. If you are a lucky owner of
  78such a laptop you will find the necessary rfkill devices under
  79/sys/class/rfkill. Check those starting with sony-* in
  80        # grep . /sys/class/rfkill/*/{state,name}
  81
  82
  83Development:
  84------------
  85
  86If you want to help with the development of this driver (and
  87you are not afraid of any side effects doing strange things with
  88your ACPI BIOS could have on your laptop), load the driver and
  89pass the option 'debug=1'.
  90
  91REPEAT: DON'T DO THIS IF YOU DON'T LIKE RISKY BUSINESS.
  92
  93In your kernel logs you will find the list of all ACPI methods
  94the SNC device has on your laptop.
  95
  96* For new models you will see a long list of meaningless method names,
  97reading the DSDT table source should reveal that:
  98(1) the SNC device uses an internal capability lookup table
  99(2) SN00 is used to find values in the lookup table
 100(3) SN06 and SN07 are used to call into the real methods based on
 101    offsets you can obtain iterating the table using SN00
 102(4) SN02 used to enable events.
 103Some values in the capability lookup table are more or less known, see
 104the code for all sony_call_snc_handle calls, others are more obscure.
 105
 106* For old models you can see the GCDP/GCDP methods used to pwer on/off
 107the CD drive, but there are others and they are usually different from
 108model to model.
 109
 110I HAVE NO IDEA WHAT THOSE METHODS DO.
 111
 112The sony-laptop driver creates, for some of those methods (the most
 113current ones found on several Vaio models), an entry under
 114/sys/devices/platform/sony-laptop, just like the 'cdpower' one.
 115You can create other entries corresponding to your own laptop methods by
 116further editing the source (see the 'sony_nc_values' table, and add a new
 117entry to this table with your get/set method names using the
 118SNC_HANDLE_NAMES macro).
 119
 120Your mission, should you accept it, is to try finding out what
 121those entries are for, by reading/writing random values from/to those
 122files and find out what is the impact on your laptop.
 123
 124Should you find anything interesting, please report it back to me,
 125I will not disavow all knowledge of your actions :)
 126
 127See also http://www.linux.it/~malattia/wiki/index.php/Sony_drivers for other
 128useful info.
 129
 130Bugs/Limitations:
 131-----------------
 132
 133* This driver is not based on official documentation from Sony
 134  (because there is none), so there is no guarantee this driver
 135  will work at all, or do the right thing. Although this hasn't
 136  happened to me, this driver could do very bad things to your
 137  laptop, including permanent damage.
 138
 139* The sony-laptop and sonypi drivers do not interact at all. In the
 140  future, sonypi will be removed and replaced by sony-laptop.
 141
 142* spicctrl, which is the userspace tool used to communicate with the
 143  sonypi driver (through /dev/sonypi) is deprecated as well since all
 144  its features are now available under the sysfs tree via sony-laptop.
 145
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