acpid trojan can mute sound on IBM/Lenovo ThinkPad laptops

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acpid trojan can mute sound on IBM/Lenovo ThinkPad laptops

Postby igorzwx » Fri Apr 19, 2013 11:37 pm

There is a special Linux trojan called "acpid"
It can mute (completely or partly) sound on IBM/Lenovo ThinkPad laptops,
and you would not be able to unmute it with OSS Mixer, or any other OSS4 tools.

acpid trojan is a "low level tool" ... board_Keys
It is a kind of rootkit deeply rooted into the Linux kernel.

On Linux Mint 13 and 14, acpid trojan is installed by default.

How to detect acpid trojan:

Code: Select all

$ ps -ef | grep acpi
root      1052     1  0 19:02 ?        00:00:00 acpid -c /etc/acpi/events -s /var/run/acpid.socket
root      1199     2  0 19:02 ?        00:00:00 [ktpacpid]
root      1200     2  0 19:02 ?        00:00:03 [ktpacpi_nvramd]
igor      9726  9623  0 21:56 pts/2    00:00:00 acpi_listen
igor     11036 10219  0 22:27 pts/1    00:00:00 grep --colour=auto acpi

On my IBM ThinkPad, there are three special multimedia keys:

Code: Select all

$ acpi_listen
ibm/hotkey HKEY 00000080 00001015 [Volume up]
ibm/hotkey HKEY 00000080 00001016 [Volume down]
ibm/hotkey HKEY 00000080 00001017 [Volume mute]

These special multimedia keys are located near the "Access IBM" button.

If OSS4 sound is muted by acpid trojan, you can unmute it with special multimedia keys, provided that those keys work.
However, such keys usually do not work on Linux. You should fix them yourself, if you know how to do this ... board_Keys

If OSS4 sound is muted (or semi-muted) by acpid trojan, and special multimedia keys do not work (this is usually the case), you would not be able to unmute it.

The OSS4 users may also experience other problems with IBM/Lenovo ThinkPad laptops, for example: viewtopic.php?f=3&t=5204

IBM/Lenovo ThinkPad hotkeys (multimedia keys) were disabled in Linux in 2009.
They can be enabled with a special secret command: ... 88#p154863 ... nd_Buttons

When the hotkeys (multimedia keys) are enabled, the pop-up notifications work as they should with MATE Desktop,
see: viewtopic.php?f=3&t=5207&start=15#p19385

- mate-settings-daemon-gstreamer (default): uses gstreamer to provide media keys.
- mate-settings-daemon-pulse: uses pulseaudio to provide media keys. ... &t=38#p123

Screenshots: viewtopic.php?f=3&t=5207&start=15#p19385

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