[alsa-devel] [PATCH] ALSA: hda - Fix Dock Headphone on Thinkpad X250 seen as a Line Out

[David Henningsson]

On 2015-06-24 14:10, Takashi Iwai wrote:
> At Wed, 24 Jun 2015 13:06:05 +0200,
> David Henningsson wrote:
>>
>>
>>
>> On 2015-06-24 11:00, Takashi Iwai wrote:
>>> At Wed, 24 Jun 2015 10:46:33 +0200,
>>> David Henningsson wrote:
>>>>
>>>> Thinkpad X250, when attached to a dock, has two headphone outs but
>>>> no line out. Make sure we don't try to turn this into one headphone
>>>> and one line out (since that disables the headphone amp on the dock).
>>>>
>>>> Alsa-info at http://www.alsa-project.org/db/?f=36f8764e1d782397928feec715d0ef90dfddd4c1
>>>>
>>>> Cc: stable at vger.kernel.org
>>>> Signed-off-by: David Henningsson <david.henningsson at canonical.com>
>>>
>>> This is one of fixes I had in mind (and asked for testing in bugzilla
>>> kernel.org report).
>>
>> Sorry, I'm missing context. What report?
>>
>>> One drawback by this is that the auto-mute
>>> *between* the headphones won't work like before.  If one has expected
>>> it, then this can be seen as a regression.
>>
>> Fair enough, we can drop stable from the patch since this could be seen
>> as behavioural change rather than bug fix.
>>
>>> Another fix was to change this as a proper line-out.  This will keep
>>> the current auto-mute behavior.
>>>
>>> OTOH, dealing both jacks equally is also not bad, per se.
>>
>> The tricky thing about routing is that everyone wants it different, so
>> pleasing everyone seems to be an impossible equation :-/
>>
>> I would choose the default behaviour (headphone or line out) based on
>> the icon on the jack. I should double-check that with someone who has
>> the hardware. And then, if someone wants another behaviour then
>> hdajackretask can be used. Or we can add a jack mode kcontrol for that
>> jack, if you prefer, although I'd have to check how PulseAudio handles
>> that (not that well, is my gut feeling).
>
> I have no preference in this regard.  My only slight concern was the
> behavior change by this patch.  It has both sides, one can see as an
> improvement while another as a regression.
>
> Currently I'm inclined to take this patch as is, since this would make
> things working in a little obstacle.  Once when we get a real
> regression report due to the lack of exclusive mute control, we may
> provide another model option as a compromise.
>
> But, I'm open about this, really.  So, if anyone has a good argument,
> let me know.

Anyhow, it looks like the current behaviour is not good, because we have 
a "Dock Headphone Jack" on the same node as "Dock Line Out Playback 
Switch". This makes me wonder if the HP -> LO fixup should be removed 
altogether. Are there any machines these days that needs this fixup? In 
case there were just a few of them in the past, maybe they should have 
pin fixups instead?

-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic