[alsa-devel] [PATCH 2/2] ALSA: hda - get realtime ELD info when codec suspended

David Henningsson david.henningsson at canonical.com
Tue Jun 25 11:02:27 CEST 2013

On 06/25/2013 09:55 AM, Takashi Iwai wrote:
> At Tue, 25 Jun 2013 09:45:04 +0200,
> David Henningsson wrote:
>>> There is a low power mode that allows the jack detection, but this is
>>> different from the aggressive power-saving with runtime D3.
>> If "aggressive power-saving with runtime D3" is the same as
>> AZX_DCAPS_PM_RUNTIME, this is also enabled for analog codecs connected
>> to a Lynx point controller.
>> It looks like userspace have problems getting notifications for e g
>> headphone insertion on Lynx point controllers, so this is not only an
>> HDMI/DP problem?
> Yes.
>> Trying to read up a little on this, there seem to be an option to set
>> the WAKEEN register to have jack detection working even when the
>> controller is in D3. (refer HDA specification
>> Codec Wake From System S0, Controller D3.)
>> But it seems we do not (yet) use this feature. Is this something that
>> could/should be implemented to fix the jack detection problems that
>> seems to be happening otherwise?
> It sounds feasible, at least for traditional jack detection of analog
> pins.  But I'm not sure whether this would help for the Intel graphics
> case.  Just need testing.

Xingchao, what are your thoughts about using WAKEEN to wakeup both Lynx 
point and Haswell HDMI?

David Henningsson, Canonical Ltd.

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