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diff --git a/Documentation/sony-laptop.txt b/Documentation/sony-laptop.txt new file mode 100644 index 00000000000..dfd26df056f --- /dev/null +++ b/Documentation/sony-laptop.txt @@ -0,0 +1,106 @@ +Sony Notebook Control Driver (SNC) Readme +----------------------------------------- + Copyright (C) 2004- 2005 Stelian Pop <stelian@popies.net> + Copyright (C) 2007 Mattia Dongili <malattia@linux.it> + +This mini-driver drives the SNC device present in the ACPI BIOS of +the Sony Vaio laptops. + +It gives access to some extra laptop functionalities. In its current +form, this driver let the user set or query the screen brightness +through the backlight subsystem and remove/apply power to some devices. + +Backlight control: +------------------ +If your laptop model supports it, you will find sysfs files in the +/sys/class/backlight/sony/ +directory. You will be able to query and set the current screen +brightness: + brightness get/set screen brightness (an iteger + between 0 and 7) + actual_brightness reading from this file will query the HW + to get real brightness value + max_brightness the maximum brightness value + + +Platform specific: +------------------ +Loading the sony-laptop module will create a +/sys/devices/platform/sony-laptop/ +directory populated with some files. + +You then read/write integer values from/to those files by using +standard UNIX tools. + +The files are: + brightness_default screen brightness which will be set + when the laptop will be rebooted + cdpower power on/off the internal CD drive + audiopower power on/off the internal sound card + lanpower power on/off the internal ethernet card + (only in debug mode) + +Note that some files may be missing if they are not supported +by your particular laptop model. + +Example usage: + # echo "1" > /sys/devices/platform/sony-laptop/brightness_default +sets the lowest screen brightness for the next and later reboots, + # echo "8" > /sys/devices/platform/sony-laptop/brightness_default +sets the highest screen brightness for the next and later reboots, + # cat /sys/devices/platform/sony-laptop/brightness_default +retrieves the value. + + # echo "0" > /sys/devices/platform/sony-laptop/audiopower +powers off the sound card, + # echo "1" > /sys/devices/platform/sony-laptop/audiopower +powers on the sound card. + +Development: +------------ + +If you want to help with the development of this driver (and +you are not afraid of any side effects doing strange things with +your ACPI BIOS could have on your laptop), load the driver and +pass the option 'debug=1'. + +REPEAT: DON'T DO THIS IF YOU DON'T LIKE RISKY BUSINESS. + +In your kernel logs you will find the list of all ACPI methods +the SNC device has on your laptop. You can see the GCDP/GCDP methods +used to pwer on/off the CD drive, but there are others. + +I HAVE NO IDEA WHAT THOSE METHODS DO. + +The sony-laptop driver creates, for some of those methods (the most +current ones found on several Vaio models), an entry under +/sys/devices/platform/sony-laptop, just like the 'cdpower' one. +You can create other entries corresponding to your own laptop methods by +further editing the source (see the 'sony_acpi_values' table, and add a new +entry to this table with your get/set method names using the +HANDLE_NAMES macro). + +Your mission, should you accept it, is to try finding out what +those entries are for, by reading/writing random values from/to those +files and find out what is the impact on your laptop. + +Should you find anything interesting, please report it back to me, +I will not disavow all knowledge of your actions :) + +Bugs/Limitations: +----------------- + +* This driver is not based on official documentation from Sony + (because there is none), so there is no guarantee this driver + will work at all, or do the right thing. Although this hasn't + happened to me, this driver could do very bad things to your + laptop, including permanent damage. + +* The sony-laptop and sonypi drivers do not interact at all. In the + future, sonypi could use sony-laptop to do (part of) its business. + +* spicctrl, which is the userspace tool used to communicate with the + sonypi driver (through /dev/sonypi) does not try to use the + sony-laptop driver. In the future, spicctrl could try sonypi first, + and if it isn't present, try sony-laptop instead. + |