[alsa-devel] Fwd: Re: Realtek ALC889: HDA Intel and kernel 3.1 gives choppy sound (again)

David Henningsson david.henningsson at canonical.com
Tue Dec 20 00:03:51 CET 2011

On 12/19/2011 04:30 PM, Takashi Iwai wrote:
> At Mon, 19 Dec 2011 16:06:53 +0100,
> David Henningsson wrote:
>> Hmm, thanks for figuring this one out. Actually this is the third time I
>> hear of jack detection flipping back and forth. I'm wondering if we need
>> (and whether other OSes have?) a filter / flood protection on this
>> stuff, and if so, how it works? I mean, nobody would notice half a
>> second of delay on that switch anyway.
> I don't think there is a perfect filtering for such a problem.
> Theoretically we can see how often it's flipped, and disables the
> jack-detection accordingly.  But not sure how useful it is in
> practice, since it's a rare case, and the manual adjustment is easy.
> BTW, maybe we should turn off the jack-detection while the auto-mute
> is disabled?  Otherwise unsol events might still come up although they
> are just ignored.

I guess that would also disable the possibility for userspace to read 
state changes, both with the old and new jack detection interface?

Also, in a long term scenario, one could consider PulseAudio disabling 
auto-mute and handling that logic itself, potentially with advanced 
routing rules (a use case could be, if a phone call comes in, play the 
ring tone in the speaker but the actual talking would be through the 

David Henningsson, Canonical Ltd.

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