sony-laptop.rst

  1=========================================
  2Sony Notebook Control Driver (SNC) Readme
  3=========================================
  4
  5	- Copyright (C) 2004- 2005 Stelian Pop <stelian@popies.net>
  6	- Copyright (C) 2007 Mattia Dongili <malattia@linux.it>
  7
  8This mini-driver drives the SNC and SPIC device present in the ACPI BIOS of the
  9Sony Vaio laptops. This driver mixes both devices functions under the same
 10(hopefully consistent) interface. This also means that the sonypi driver is
 11obsoleted by sony-laptop now.
 12
 13Fn keys (hotkeys):
 14------------------
 15
 16Some models report hotkeys through the SNC or SPIC devices, such events are
 17reported both through the ACPI subsystem as acpi events and through the INPUT
 18subsystem. See the logs of /proc/bus/input/devices to find out what those
 19events are and which input devices are created by the driver.
 20Additionally, loading the driver with the debug option will report all events
 21in the kernel log.
 22
 23The "scancodes" passed to the input system (that can be remapped with udev)
 24are indexes to the table "sony_laptop_input_keycode_map" in the sony-laptop.c
 25module.  For example the "FN/E" key combination (EJECTCD on some models)
 26generates the scancode 20 (0x14).
 27
 28Backlight control:
 29------------------
 30If your laptop model supports it, you will find sysfs files in the
 31/sys/class/backlight/sony/
 32directory. You will be able to query and set the current screen
 33brightness:
 34
 35	======================	=========================================
 36	brightness		get/set screen brightness (an integer
 37				between 0 and 7)
 38	actual_brightness	reading from this file will query the HW
 39				to get real brightness value
 40	max_brightness		the maximum brightness value
 41	======================	=========================================
 42
 43
 44Platform specific:
 45------------------
 46Loading the sony-laptop module will create a
 47/sys/devices/platform/sony-laptop/
 48directory populated with some files.
 49
 50You then read/write integer values from/to those files by using
 51standard UNIX tools.
 52
 53The files are:
 54
 55	======================	==========================================
 56	brightness_default	screen brightness which will be set
 57				when the laptop will be rebooted
 58	cdpower			power on/off the internal CD drive
 59	audiopower		power on/off the internal sound card
 60	lanpower		power on/off the internal ethernet card
 61				(only in debug mode)
 62	bluetoothpower		power on/off the internal bluetooth device
 63	fanspeed		get/set the fan speed
 64	======================	==========================================
 65
 66Note that some files may be missing if they are not supported
 67by your particular laptop model.
 68
 69Example usage::
 70
 71	# echo "1" > /sys/devices/platform/sony-laptop/brightness_default
 72
 73sets the lowest screen brightness for the next and later reboots
 74
 75::
 76
 77	# echo "8" > /sys/devices/platform/sony-laptop/brightness_default
 78
 79sets the highest screen brightness for the next and later reboots
 80
 81::
 82
 83	# cat /sys/devices/platform/sony-laptop/brightness_default
 84
 85retrieves the value
 86
 87::
 88
 89	# echo "0" > /sys/devices/platform/sony-laptop/audiopower
 90
 91powers off the sound card
 92
 93::
 94
 95	# echo "1" > /sys/devices/platform/sony-laptop/audiopower
 96
 97powers on the sound card.
 98
 99
100RFkill control:
101---------------
102More recent Vaio models expose a consistent set of ACPI methods to
103control radio frequency emitting devices. If you are a lucky owner of
104such a laptop you will find the necessary rfkill devices under
105/sys/class/rfkill. Check those starting with sony-* in::
106
107	# grep . /sys/class/rfkill/*/{state,name}
108
109
110Development:
111------------
112
113If you want to help with the development of this driver (and
114you are not afraid of any side effects doing strange things with
115your ACPI BIOS could have on your laptop), load the driver and
116pass the option 'debug=1'.
117
118REPEAT:
119	**DON'T DO THIS IF YOU DON'T LIKE RISKY BUSINESS.**
120
121In your kernel logs you will find the list of all ACPI methods
122the SNC device has on your laptop.
123
124* For new models you will see a long list of meaningless method names,
125  reading the DSDT table source should reveal that:
126
127(1) the SNC device uses an internal capability lookup table
128(2) SN00 is used to find values in the lookup table
129(3) SN06 and SN07 are used to call into the real methods based on
130    offsets you can obtain iterating the table using SN00
131(4) SN02 used to enable events.
132
133Some values in the capability lookup table are more or less known, see
134the code for all sony_call_snc_handle calls, others are more obscure.
135
136* For old models you can see the GCDP/GCDP methods used to pwer on/off
137  the CD drive, but there are others and they are usually different from
138  model to model.
139
140**I HAVE NO IDEA WHAT THOSE METHODS DO.**
141
142The sony-laptop driver creates, for some of those methods (the most
143current ones found on several Vaio models), an entry under
144/sys/devices/platform/sony-laptop, just like the 'cdpower' one.
145You can create other entries corresponding to your own laptop methods by
146further editing the source (see the 'sony_nc_values' table, and add a new
147entry to this table with your get/set method names using the
148SNC_HANDLE_NAMES macro).
149
150Your mission, should you accept it, is to try finding out what
151those entries are for, by reading/writing random values from/to those
152files and find out what is the impact on your laptop.
153
154Should you find anything interesting, please report it back to me,
155I will not disavow all knowledge of your actions :)
156
157See also http://www.linux.it/~malattia/wiki/index.php/Sony_drivers for other
158useful info.
159
160Bugs/Limitations:
161-----------------
162
163* This driver is not based on official documentation from Sony
164  (because there is none), so there is no guarantee this driver
165  will work at all, or do the right thing. Although this hasn't
166  happened to me, this driver could do very bad things to your
167  laptop, including permanent damage.
168
169* The sony-laptop and sonypi drivers do not interact at all. In the
170  future, sonypi will be removed and replaced by sony-laptop.
171
172* spicctrl, which is the userspace tool used to communicate with the
173  sonypi driver (through /dev/sonypi) is deprecated as well since all
174  its features are now available under the sysfs tree via sony-laptop.