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

[Takashi Iwai]

At Wed, 24 Jun 2015 15:23:24 +0200,
Takashi Iwai wrote:
> 
> At Wed, 24 Jun 2015 14:33:52 +0200,
> David Henningsson wrote:
> > 
> > 
> > 
> > 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?
> 
> Yes, this is one good step forward.  We should check through hda-emu.
> 
> Though, for the problem of Thinkpads, I prefer a patch with a smaller
> impact like yours.

FYI, I applied the patch now.  Let's continue working on top of it.

thanks,


Takashi