Re: [RFC PATCH 0/2] ALSA: hda - DP MST audio for Jack support

[Takashi Iwai <tiwai@suse.de>]

On Wed, 04 Nov 2015 07:23:14 +0100,
Libin Yang wrote:
> 
> 
> On 11/04/2015 12:49 AM, Takashi Iwai wrote:
> > On Tue, 03 Nov 2015 09:42:54 +0100,
> > libin.yang@linux.intel.com wrote:
> >>
> >> From: Libin Yang <libin.yang@linux.intel.com>
> >>
> >> This is the patch set for Jack support for DP MST audio
> >>
> >> Libin Yang (2):
> >>    ALSA: hda - jack support DP MST audio
> >>    ALSA: hda - hdmi audio add dynamically jack binding to pin
> >
> > I'm somehow confused by this patch series.
> > Is the unsolicited event handling itself changed for MST?  I mean, you
> > cannot know which MST dev# is given beforehand, while you seem trying
> > to assign such a number to the jack object.
> 
> Oh, sorry I forgot to mention that we only operate on device entry 0 
> so far in the code. It's misleading.
> 
> These patches don't operate on MST audio. The full MST audio driver 
> support will be implemented in the later patches. The patches help to 
> prepare supporting MST audio.
> 
> The purpose of the patches is try to dynamically attach the Jack.

Well, only judging from the quick glance, I don't buy this strategy,
sorry.  Currently for HDMI/DP, the jack is for PCM, not for pin.
Namely, user-space watches the jack notification to judge whether the
corresponding PCM is available or not.  You're trying to change this
scheme completely.

So, please convince us why this change is needed and which merit /
demerit it'll bring.  Let's start from that point.


thanks,

Takashi