Re: [PATCH] ALSA: hda_intel: add AZX_DCAPS_I915_POWERWELL for skl

[Takashi Iwai <tiwai@suse.de>]

At Fri, 27 Mar 2015 08:02:54 +0000,
Yang, Libin wrote:
> 
> Hi Takashi,
> 
> 
> 
> > -----Original Message-----
> > From: Takashi Iwai [mailto:tiwai@suse.de]
> > Sent: Friday, March 27, 2015 3:57 PM
> > To: Yang, Libin
> > Cc: alsa-devel@alsa-project.org
> > Subject: Re: [PATCH] ALSA: hda_intel: add
> > AZX_DCAPS_I915_POWERWELL for skl
> > 
> > At Fri, 27 Mar 2015 15:10:04 +0800,
> > libin.yang@intel.com wrote:
> > >
> > > From: Libin Yang <libin.yang@intel.com>
> > >
> > > HDMI/DP codec on SKL is in the power well.
> > > The power well must be turned on before probing the
> > > HDMI/DP codec.
> > >
> > > Signed-off-by: Libin Yang <libin.yang@intel.com>
> > 
> > So, was the previous question clarified?
> 
> Yes, I have confirmed with our silicon team.
> 
> > 
> > This certainly sucks.  It means that the powerwell is on even you
> > don't use the HDMI/DP at all.  If this is intended as a temporarily
> > workaround, it should be mentioned so.  Please give more comments
> > and
> > backgrounds.
> 
> Yes, as this is added in the skl audio controller, even there is no HDMI/DP
> codec, we should also add this flag. Otherwise the HDMI/DP codec
> may not be detected correctly.

But it's possible to do it only at probing, not permanently.  If so,
we'll have another patch in future.

Please write more information in the changelog and resubmit.


Takashi