Documentation/sony-laptop.txt

   1 Sony 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
   6 This mini-driver drives the SNC and SPIC device present in the ACPI BIOS of the
   7 Sony Vaio laptops. This driver mixes both devices functions under the same
   8 (hopefully consistent) interface. This also means that the sonypi driver is
   9 obsoleted by sony-laptop now.
  10
  11 Fn keys (hotkeys):
  12 ------------------
  13 Some models report hotkeys through the SNC or SPIC devices, such events are
  14 reported both through the ACPI subsystem as acpi events and through the INPUT
  15 subsystem. 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
  17 devices are created by the driver.
  18
  19 Backlight control:
  20 ------------------
  21 If your laptop model supports it, you will find sysfs files in the
  22 /sys/class/backlight/sony/
  23 directory. You will be able to query and set the current screen
  24 brightness:
  25         brightness              get/set screen brightness (an iteger
  26                                 between 0 and 7)
  27         actual_brightness       reading from this file will query the HW
  28                                 to get real brightness value
  29         max_brightness          the maximum brightness value
  30
  31
  32 Platform specific:
  33 ------------------
  34 Loading the sony-laptop module will create a
  35 /sys/devices/platform/sony-laptop/
  36 directory populated with some files.
  37
  38 You then read/write integer values from/to those files by using
  39 standard UNIX tools.
  40
  41 The files are:
  42         brightness_default      screen brightness which will be set
  43                                 when the laptop will be rebooted
  44         cdpower                 power on/off the internal CD drive
  45         audiopower              power on/off the internal sound card
  46         lanpower                power on/off the internal ethernet card
  47                                 (only in debug mode)
  48         bluetoothpower          power on/off the internal bluetooth device
  49         fanspeed                get/set the fan speed
  50
  51 Note that some files may be missing if they are not supported
  52 by your particular laptop model.
  53
  54 Example usage:
  55         # echo "1" > /sys/devices/platform/sony-laptop/brightness_default
  56 sets the lowest screen brightness for the next and later reboots,
  57         # echo "8" > /sys/devices/platform/sony-laptop/brightness_default
  58 sets the highest screen brightness for the next and later reboots,
  59         # cat /sys/devices/platform/sony-laptop/brightness_default
  60 retrieves the value.
  61
  62         # echo "0" > /sys/devices/platform/sony-laptop/audiopower
  63 powers off the sound card,
  64         # echo "1" > /sys/devices/platform/sony-laptop/audiopower
  65 powers on the sound card.
  66
  67 Development:
  68 ------------
  69
  70 If you want to help with the development of this driver (and
  71 you are not afraid of any side effects doing strange things with
  72 your ACPI BIOS could have on your laptop), load the driver and
  73 pass the option 'debug=1'.
  74
  75 REPEAT: DON'T DO THIS IF YOU DON'T LIKE RISKY BUSINESS.
  76
  77 In your kernel logs you will find the list of all ACPI methods
  78 the SNC device has on your laptop. You can see the GCDP/GCDP methods
  79 used to pwer on/off the CD drive, but there are others.
  80
  81 I HAVE NO IDEA WHAT THOSE METHODS DO.
  82
  83 The sony-laptop driver creates, for some of those methods (the most
  84 current ones found on several Vaio models), an entry under
  85 /sys/devices/platform/sony-laptop, just like the 'cdpower' one.
  86 You can create other entries corresponding to your own laptop methods by
  87 further editing the source (see the 'sony_nc_values' table, and add a new
  88 entry to this table with your get/set method names using the
  89 SNC_HANDLE_NAMES macro).
  90
  91 Your mission, should you accept it, is to try finding out what
  92 those entries are for, by reading/writing random values from/to those
  93 files and find out what is the impact on your laptop.
  94
  95 Should you find anything interesting, please report it back to me,
  96 I will not disavow all knowledge of your actions :)
  97
  98 See also http://www.linux.it/~malattia/wiki/index.php/Sony_drivers for other
  99 useful info.
 100
 101 Bugs/Limitations:
 102 -----------------
 103
 104 * This driver is not based on official documentation from Sony
 105   (because there is none), so there is no guarantee this driver
 106   will work at all, or do the right thing. Although this hasn't
 107   happened to me, this driver could do very bad things to your
 108   laptop, including permanent damage.
 109
 110 * The sony-laptop and sonypi drivers do not interact at all. In the
 111   future, sonypi could use sony-laptop to do (part of) its business.
 112
 113 * spicctrl, which is the userspace tool used to communicate with the
 114   sonypi driver (through /dev/sonypi) does not try to use the
 115   sony-laptop driver. In the future, spicctrl could try sonypi first,
 116   and if it isn't present, try sony-laptop instead.
 117