A kernel simple module that enables you to call ACPI methods by writing the
method name followed by arguments to /proc/acpi/call.
This module is to be considered a proof-of-concept and has been superseeded by projects like bbswitch. It allows you to tamper with your system and should be used with caution.
Want to use acpi_call via graphic interface? Click here
Usage:
echo '<call>' | sudo tee /proc/acpi/call
You can then retrieve the result of the call by checking your dmesg or:
sudo cat /proc/acpi/call
An example to turn off discrete graphics card in a dual graphics environment (like NVIDIA Optimus):
# turn off discrete graphics card
echo '\_SB.PCI0.PEG1.GFX0.DOFF' > /proc/acpi/call
# turn it back on
echo '\_SB.PCI0.PEG1.GFX0.DON' > /proc/acpi/call
These work on my ASUS K52J notebook, but may not work for you. For a list of
methods to try, see http://linux-hybrid-graphics.blogspot.com/ or try running
the provided script examples/turn_off_gpu.sh
It SHOULD be ok to test all of the methods, until you see a drop in battery
drain rate (grep rate /proc/acpi/battery/BAT0/state), however it comes
with NO WARRANTY - it may hang your computer/laptop, fail to work, etc.
You can pass parameters to acpi_call by writing them after the method,
separated by single space. Currently, you can pass the following parameter
types:
- ACPI_INTEGER - by writing NNN or 0xNNN, where NNN is an integer/hex
- ACPI_STRING - by enclosing the string in quotes: "hello, world"
- ACPI_BUFFER - by writing bXXXX, where XXXX is a hex string without spaces, or by writing { b1, b2, b3, b4 }, where b1-4 are integers
The status after a call can be read back from /proc/acpi/call:
- 'not called' - nothing to report
- 'Error: ' - the call failed
- '0xNN' - the call succeeded, and returned an integer
- '"..."' - the call succeeded, and returned a string
- '{0xNN, ...}' - the call succeeded, and returned a buffer
- '[...]' - the call succeeded, and returned a package which may contain the above types (integer, string and buffer) and other package types
Found this too difficult? Try to use these programs provided by Marco Dalla Libera and do it via graphic interface:
Copyright (c) 2010: Michal Kottman
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.