Feature #74
openLenovo X200 Mute button mutes with the EC, not in software
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Description
This has the side effect of only muting the speakers, and is not toggleable.
Audio playing; press mute; muted audio (OS shows volume on still); press mute; still muted audio;
This was (in the Lenovo BIOS) toggleable with an ACPI cmdline tweak to the kernel. [1] However when I tried this a while ago it didn't work (I presume that CB doesn't replicate this behavior).
Updated by lx r over 7 years ago
The behaviour should be configurable. There are 2 bits reserved to configure this behaviour.
See bit 5-6 (count from 0) in 0x3 of the EC memory.
You can change those bits using ectool under coreboot.git/util/ectool.
./ectool -d
dumps the whole memory (a special buffer on the EC).
Read out the byte on 0x3 and play a little bit with bit 5-6
./ectools -w 0x3 -z 0xXX
Updated by Arthur Heymans over 6 years ago
So do we implement an nvram parameter for this (so it is static and needs a reset/s3 cycle for it to be applied) or an ACPI method to change it during runtime with the acpi_call module or both?
Updated by Patrick Rudolph over 6 years ago
The thinkpad_acpi kernel module knows about the "hardware mute" and should be able to handle it, as it's not coreboot specific. I'll do some tests on T500.