[alsa-devel] [PATCH] ALSA: hda - Re-setup HDMI pin and audio infoframe on stream switches

[Takashi Iwai]

At Tue, 03 Sep 2013 13:10:43 +0200,
David Henningsson wrote:
> 
> On 09/03/2013 11:57 AM, Takashi Iwai wrote:
> > When the transcoder:port mapping on Haswell HDMI/DP audio is changed
> > during the stream playback, the sound gets lost.  Typically this
> > problem is seen when the user switches the graphics mode from eDP+DP
> > to DP-only configuration, where CRTC 1 is used for DP in the former
> > while CRTC 0 is used for the latter.
> > 
> > The graphics controller notifies the change via the normal ELD update
> > procedure, so we get the intrinsic event.  For enabling the sound
> > again, the HDMI audio driver needs to reset the pin and set up the
> > audio infoframe again.
> 
> Thanks for working on this!
> 
> See a review comment below.
> 
> > 
> > This patch achieves it by:
> > - keep the current status of channels and info frame setup in per_pin
> >   struct,
> > - check the reconnection in the intrinsic event handler,
> > - reset the pin and the re-invoke hdmi_setup_audio_infoframe()
> >   accordingly.
> > 
> > The hdmi_setup_audio_infoframe() function has been changed, too, so
> > that it can be invoked without passing the substream instance.
> > 
> > The patch is mostly based on the work by Mengdong Lin.
> > 
> > Cc: Mengdong Lin <mengdong.lin at intel.com>
> > Cc: <stable at vger.kernel.org>
> > Signed-off-by: Takashi Iwai <tiwai at suse.de>
> > ---
> >  sound/pci/hda/patch_hdmi.c | 41 +++++++++++++++++++++++++++++++----------
> >  1 file changed, 31 insertions(+), 10 deletions(-)
> > 
> > diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
> > index b83b14f..22b5089 100644
> > --- a/sound/pci/hda/patch_hdmi.c
> > +++ b/sound/pci/hda/patch_hdmi.c
> > @@ -67,6 +67,8 @@ struct hdmi_spec_per_pin {
> >  	struct delayed_work work;
> >  	struct snd_kcontrol *eld_ctl;
> >  	int repoll_count;
> > +	bool setup; /* the stream has been set up by prepare callback */
> > +	int channels; /* current number of channels */
> >  	bool non_pcm;
> >  	bool chmap_set;		/* channel-map override by ALSA API? */
> >  	unsigned char chmap[8]; /* ALSA API channel-map */
> > @@ -879,18 +881,19 @@ static bool hdmi_infoframe_uptodate(struct hda_codec *codec, hda_nid_t pin_nid,
> >  	return true;
> >  }
> >  
> > -static void hdmi_setup_audio_infoframe(struct hda_codec *codec, int pin_idx,
> > -				       bool non_pcm,
> > -				       struct snd_pcm_substream *substream)
> > +static void hdmi_setup_audio_infoframe(struct hda_codec *codec,
> > +				       struct hdmi_spec_per_pin *per_pin,
> > +				       bool non_pcm)
> >  {
> > -	struct hdmi_spec *spec = codec->spec;
> > -	struct hdmi_spec_per_pin *per_pin = get_pin(spec, pin_idx);
> >  	hda_nid_t pin_nid = per_pin->pin_nid;
> > -	int channels = substream->runtime->channels;
> > +	int channels = per_pin->channels;
> >  	struct hdmi_eld *eld;
> >  	int ca;
> >  	union audio_infoframe ai;
> >  
> > +	if (!channels)
> > +		return;
> > +
> >  	eld = &per_pin->sink_eld;
> >  	if (!eld->monitor_present)
> >  		return;
> > @@ -1341,6 +1344,7 @@ static void hdmi_present_sense(struct hdmi_spec_per_pin *per_pin, int repoll)
> >  		eld_changed = true;
> >  	}
> >  	if (update_eld) {
> > +		bool old_eld_valid = pin_eld->eld_valid;
> >  		pin_eld->eld_valid = eld->eld_valid;
> >  		eld_changed = pin_eld->eld_size != eld->eld_size ||
> >  			      memcmp(pin_eld->eld_buffer, eld->eld_buffer,
> > @@ -1350,6 +1354,18 @@ static void hdmi_present_sense(struct hdmi_spec_per_pin *per_pin, int repoll)
> >  			       eld->eld_size);
> >  		pin_eld->eld_size = eld->eld_size;
> >  		pin_eld->info = eld->info;
> > +
> > +		/* Haswell-specific workaround: re-setup when the transcoder is
> > +		 * changed during the stream playback
> > +		 */
> > +		if (codec->vendor_id == 0x80862807 &&
> > +		    eld->eld_valid && !old_eld_valid && per_pin->setup) {
> > +			snd_hda_codec_write(codec, pin_nid, 0,
> > +					    AC_VERB_SET_AMP_GAIN_MUTE,
> > +					    AMP_OUT_UNMUTE);
> 
> If the system is deliberately muted by turning off "IEC958 Playback
> Switch", are we now ignoring that and turning it back on?

The pin amp is always unmuted.  The IEC958 Playback Switch is
controlled via IEC958 status bits instead.

> Also, this looks a bit like the workaround I added a while back
> (83f26ad2c909083fa6 - ALSA: hda - fixup D3 pin and right channel mute on
> Haswell HDMI audio) is there a possibility we need to fix up D3 as well
> here? I e, call haswell_verify_pin_D0 rather than just setting the mute?
> Or perhaps move the call to haswell_verify_pin_D0 from hdmi_setup_stream
> to hdme_setup_audio_infoframe ?

The power state is fine in this case, but just to reset the amp state
by some reason.  It's not enough to update the info frame, as far as I
tested.


thanks,

Takashi