If alsamixer handles this correctly it may be that the alsamixer code is the documentation.
Alsamixer just always does the conversion by itself...In fact that's the idea of my patch - I've just directly copied translation code to kmix.
And it seems alsamixer does the translation since a very long time ago, so I don't really understand how everything worked before... O_o
Sound cards are built-in intel ones on all the machines on which the bug does reproduce (snd-hda-intel driver).
Are you able to revert the issue by installing libasound2 1.0.27.2-1 ? If that's the case a bisect might be productive.
Hm... I'll try to revert it. -- With best regards, Vitaliy Filippov