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Diffstat (limited to 'Documentation/acpi/sony_acpi.txt')
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diff --git a/Documentation/acpi/sony_acpi.txt b/Documentation/acpi/sony_acpi.txt new file mode 100644 index 000000000000..35a04bea38d7 --- /dev/null +++ b/Documentation/acpi/sony_acpi.txt @@ -0,0 +1,87 @@ +ACPI Sony Notebook Control Driver (SNC) Readme +---------------------------------------------- + Copyright (C) 2004- 2005 Stelian Pop <stelian@popies.net> + +This mini-driver drives the ACPI 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 is mainly useful for controlling the +screen brightness, but it may do more in the future. + +You should probably start by trying the sonypi driver, and try +sony_acpi only if sonypi doesn't work for you. + +Usage: +------ + +Loading the sony_acpi module will create a /proc/acpi/sony/ +directory populated with a couple of files. + +You then read/write integer values from/to those files by using +standard UNIX tools. + +The files are: + brightness current screen brightness + brightness_default screen brightness which will be set + when the laptop will be rebooted + cdpower power on/off the internal CD drive + +Note that some files may be missing if they are not supported +by your particular laptop model. + +Example usage: + # echo "1" > /proc/acpi/sony/brightness +sets the lowest screen brightness, + # echo "8" > /proc/acpi/sony/brightness +sets the highest screen brightness, + # cat /proc/acpi/sony/brightness +retrieves the current screen brightness. + +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 GBRT/SBRT methods +used to get/set the brightness, but there are others. + +I HAVE NO IDEA WHAT THOSE METHODS DO. + +The sony_acpi driver creates, for some of those methods (the most +current ones found on several Vaio models), an entry under +/proc/acpi/sony/, just like the 'brightness' 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 +structure to this table with your get/set method names). + +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_acpi and sonypi drivers do not interact at all. In the + future, sonypi could use sony_acpi 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_acpi driver. In the future, spicctrl could try sonypi first, + and if it isn't present, try sony_acpi instead. + |