[alsa-devel] Regression for Lenovo X240 sound in 3.18

[Jan Engelhardt]

I have a X240 (without any dock), and in Linux 3.17.4, I used to have
- "Speaker" with switch and volume bar (in alsamixer),
- "PCM" with switch and volume bar,
- the headphone output volume would be controlled by both Master and PCM.

With 3.18.1, bisected down to below commit, this all went bonkers.
- "Speaker" has only a switch but no volume bar,
- speakers do not output _any_ sound whatsoever anymore
- changing the PCM volume does not affect either Headphone or Speaker.


commit 7c21539c45eace48e9f6fbdd59347d8416960af5
Author: Lukas Bossard <mr.bobukas at gmail.com>
Date:   Wed Oct 29 18:31:07 2014 +0100

    ALSA: hda - Add ultra dock support for Thinkpad X240.
    
    Adding ultra doch support for Lenovo Thinkpad X240 (17aa:2214).
    [Actually replaced the entry with ALC292_FIXUP_TPT440_DOCK -- tiwai]


Reverting this commit on top of v3.18.1 restores the sought 
functionality.