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A kernel module that enables you to call ACPI methods by writing the method
name followed by arguments to /proc/acpi/call.
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 or try running
the provided script
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
You can pass parameters to acpi_call by writing them after the method,
separated by single space. Currently, you can pass the following parameter
* 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: <description>' - 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
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
GNU General Public License for more details.
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