[alsa-devel] [PATCH] ALSA: hda - Remove ignore_misc_bit

[David Henningsson]

On 09/07/2012 01:59 PM, Takashi Iwai wrote:
> At Fri, 07 Sep 2012 13:26:35 +0200,
> David Henningsson wrote:
>>
>> On 09/07/2012 12:01 PM, Takashi Iwai wrote:
>>> At Fri,  7 Sep 2012 07:25:44 +0200,
>>> David Henningsson wrote:
>>>>
>>>> The purpose of this flag is unclear. If the problem is that some machines
>>>> have broken misc/NO_PRESENCE bits, they should be fixed by pin fixups.
>>>>
>>>> In addition, this causes jack detection functionality to be flawed on
>>>> the M31EI, where there are two jacks without jack detection (which is
>>>> properly marked as NO_PRESENCE), but due to ignore_misc_bit, these
>>>> jacks are instead being reported as being present but always unplugged.
>>>>
>>>> BugLink: https://bugs.launchpad.net/bugs/939161
>>>> Signed-off-by: David Henningsson <david.henningsson at canonical.com>
>>>
>>> So this will fix this one case but will break some others certainly.
>>> It's a difficult to judge, but more removal is better, so I'll take
>>> this.
>>
>> Ok. Do you have a sense for how many machines that will regress due to
>> this patch? If it is common to set all pins to the wrong value, maybe
>> its the M31EI that is the exception.
>
> Maybe a few Acer and ASUS ones with old codecs.
> Possibly some desktops with unknown mobos might hit, but that's not
> what I do care so much for now.

Hrm, ok. I still don't like the idea of regressing machines...maybe this 
patch needs further research.

>>> But I still wonder why PulseAudio cares the headphone jack state even
>>> though this has only one output at all?
>>
>> When seeing the system as a whole, there can be other outputs on other
>> cards - HDMI, USB etc. If somebody e g plugs a USB headset in it will be
>> simpler for the user if PulseAudio does not also show the unplugged 3.5
>> mm jack.
>
> OK, but masking it out unconditionally isn't always nice.  There are
> always corner cases...

Not sure what corner case you mean here, but if you like, you can 
configure this behaviour in 
/usr/share/pulseaudio/alsa-mixer/paths/analog-output-headphones.conf, 
causing the jack detection to be ignored if you prefer. And you can 
quirk a specific machine to use another .conf file based on udev rules.

Or is the corner case that ALSA don't give the correct jack detection 
value? If so I prefer it to be fixed in ALSA ;-)


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