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

[David Henningsson]

On 09/03/2013 02:06 PM, Takashi Iwai wrote:
> 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.

Ok.

> 
>> 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.

Ok - maybe Mengdong can comment more on this, if it's the same scenario
as I was working around earlier (right channel muted and pin in D3), or
if this is something different.

If it's the same issue, I was thinking that we could
 1) skip the extra snd_hda_codec_write here, and
 2) move the call to haswell_verify_pin_D0 from hdmi_setup_stream to
hdmi_setup_audio_infoframe?

Also, if the pin amp is always unmuted, we could speed up
haswell_verify_pin_D0 to always unmute instead of read-then-write.


-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic