[alsa-devel] [pulseaudio-discuss] ThinkPad T-510 audio output mute LED non-workingness

[Raymond Yau]

>
> Here are the XXX messages:
>
>     [   13.722755] sound hdaudioC0D0: XXX hda_fixup_thinkpad_acpi init...
>     [   13.724366] sound hdaudioC0D0: XXX ok, this is thinkpad
>     [   13.724373] sound hdaudioC0D0: XXX mute LED NOT WORKING!
>

This mean that your thinkpad does not support SSMS interface


>     [   13.724374] sound hdaudioC0D0: XXX ok, mic LED is hooked
>

This mean that your thinkpad support MMTS interface


http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/platform/x86/thinkpad_acpi.c?id=9a417ec0c9d1f7af5394333411fc4d98adb8761b

it look like you still need hardware mute gate to turn on/off mute led if
there is no other way to turn mute led on/off

but need the MMTS to turn on/off mic mute led

https://lists.launchpad.net/hybrid-graphics-linux/msg01387.html

Do T420 support SSMS interface ?