[alsa-devel] [PATCH v2 00/11] drm/i915: LPE audio runtime PM and multipipe (v2)

[Ville Syrjälä]

On Fri, Apr 28, 2017 at 10:41:37AM +0200, Takashi Iwai wrote:
> On Thu, 27 Apr 2017 18:02:19 +0200,
> ville.syrjala at linux.intel.com wrote:
> > 
> > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > 
> > Okay, here's the second attempt at getting multiple pipes playing back
> > audio on the VLV/CHV HDMI LPE audio device. The main change from v1 is
> > that now the PCM devices are associated with ports instead of pipes,
> > so the audio from one device always gets output on the same display.
> > 
> > I've also tacked on the alsa-lib conf update. No clue whether it's
> > really correct or not (the config language isn't a close friend
> > of mine).
> > 
> > BTW I did notice that with LPE audio all the controls say iface=PCM,
> > whereas on HDA a bunch of them say iface=MIXER. No idea if that's
> > OK or not, just something I spotted when I was comparing the results
> > with HDA.
> 
> We generally accept both iface types for IEC958 stuff, since
> historically many drivers have already mixed them up.  So it's no
> problem :)
> 
> 
> > Entire series available here:
> > git://github.com/vsyrjala/linux.git lpe_audio_multipipe_2
> > 
> > Cc: Takashi Iwai <tiwai at suse.de>
> > Cc: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
> 
> All look good, and feel free to take my reviewed-by tag
>   Reviewed-by: Takashi Iwai <tiwai at suse.de>

Thanks.

> 
> As said previously, my only slight concern is the compatibility.
> But, in the current situation with PulseAudio, only few people would
> use this driver, so it shouldn't be so big impact, I suppose.

What will break? Or you mean the alsa-lib vs. kernel difference
until they sync up? I don't use pulse myself so I don't know really
what it wants.

> 
> BTW, which port is used in general on BYT/CHT?

There's no clear rule I think. But I suppose most manufacturers
follow some reference design, so there could be some layouts
that are more common than other. Having HDMI on port D on CHV
is a fairly common design I've seen. And I think all the
pre-production RVP boards had eDP on port C, so that could also
be how production boards tend to be wired up.

> Oh, also, I suppose you want to carry these over i915 tree?
> I don't mind either way, I can take them through sound tree if
> preferred, too.

Cool. I just pushed the lot to drm-intel-next-queued. I'm
thinking going via dinq might avoid some conflicts later on
if we end up churning the code some more. And we do like to
churn ;)

-- 
Ville Syrjälä
Intel OTC