Re: [PATCH v4 4/5] ALSA: hda - hdmi dynamically bind PCM to pin when monitor hotplug

[Libin Yang <libin.yang@linux.intel.com>]

On 12/16/2015 03:43 PM, Takashi Iwai wrote:
> On Wed, 16 Dec 2015 06:42:44 +0100,
> libin.yang@linux.intel.com wrote:
>>
>> From: Libin Yang <libin.yang@linux.intel.com>
>>
>> Dynamically bind/unbind the PCM to pin when HDMI/DP monitor hotplug.
>>
>> When monitor is connected, find a proper PCM for the monitor.
>> When monitor is disconnected, unbind the PCM from the pin.
>>
>> The binding policy (use Intel platform as example) is:
>> 1. Try to use the legacy pin-pcm mapping for the device entry 0
>>     of the pin.
>> 2. If step 1 fails, try to bind pin to the backup PCMs. For example,
>>     on Intel platform, if DP MST is enabled, 5 PCMs will be created.
>>     PCM 3, PCM 7, PCM 8 are supposed to be used by device entry 0 of
>>     pin 5, pin 6 and pin 7. PCM 9 and PCM 10 are the backup PCMs.
>> 3. If step 2 fails, try to find any PCM to bind to the pin.
>>
>> Signed-off-by: Libin Yang <libin.yang@linux.intel.com>
>
> This patch adds the code in sync_eld_via_acomp(), i.e. it's handled
> only with component.  As the dynamic HDA attach/detach itself is
> agnostic to the component, I'd suggest to put this rather in
> update_eld().
>
> Also pcm_lock can be put in hdmi_present_sense() to wrap both
> sync_eld_via_acomp() and hdmi_present_sense_via_verbs().

OK, I will put it in update_eld().

Best Regards,
Libin

>
>
> Takashi
>
>> ---
>>   sound/pci/hda/patch_hdmi.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 73 insertions(+)
>>
>> diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
>> index 19bf782..10edab8 100644
>> --- a/sound/pci/hda/patch_hdmi.c
>> +++ b/sound/pci/hda/patch_hdmi.c
>> @@ -73,6 +73,8 @@ struct hdmi_spec_per_cvt {
>>
>>   struct hdmi_spec_per_pin {
>>   	hda_nid_t pin_nid;
>> +	/* pin idx, different device entries on the same pin use the same idx */
>> +	int pin_nid_idx;
>>   	int num_mux_nids;
>>   	hda_nid_t mux_nids[HDA_MAX_CONNECTIONS];
>>   	int mux_idx;
>> @@ -85,6 +87,7 @@ struct hdmi_spec_per_pin {
>>   	struct snd_kcontrol *eld_ctl;
>>   	struct snd_jack *acomp_jack; /* jack via audio component */
>>   	struct hda_pcm *pcm; /* pointer to spec->pcm_rec[n] dynamically*/
>> +	int pcm_idx; /* which pcm is attached. -1 means no pcm is attached */
>>   	int repoll_count;
>>   	bool setup; /* the stream has been set up by prepare callback */
>>   	int channels; /* current number of channels */
>> @@ -138,6 +141,8 @@ struct hdmi_spec {
>>   	struct snd_array pins; /* struct hdmi_spec_per_pin */
>>   	struct hda_pcm *pcm_rec[16];
>>   	struct mutex pcm_lock;
>> +	/* pcm_bitmap means which pcms have been assigned to pins*/
>> +	unsigned long pcm_bitmap;
>>   	int pcm_used;	/* counter of pcm_rec[] */
>>   	unsigned int channels_max; /* max over all cvts */
>>
>> @@ -1786,6 +1791,60 @@ static bool hdmi_present_sense_via_verbs(struct hdmi_spec_per_pin *per_pin,
>>   	return ret;
>>   }
>>
>> +static int hdmi_find_pcm_slot(struct hdmi_spec *spec,
>> +				struct hdmi_spec_per_pin *per_pin)
>> +{
>> +	int i;
>> +
>> +	/* try the prefer PCM */
>> +	if (!test_bit(per_pin->pin_nid_idx, &spec->pcm_bitmap))
>> +		return per_pin->pin_nid_idx;
>> +
>> +	/* have a second try; check the "reserved area" over num_pins */
>> +	for (i = spec->num_pins; i < spec->pcm_used; i++) {
>> +		if (!test_bit(i, &spec->pcm_bitmap))
>> +			return i;
>> +	}
>> +
>> +	/* the last try; check the empty slots in pins */
>> +	for (i = 0; i < spec->num_pins; i++) {
>> +		if (!test_bit(i, &spec->pcm_bitmap))
>> +			return i;
>> +	}
>> +	return -EBUSY;
>> +}
>> +
>> +static void hdmi_attach_hda_pcm(struct hdmi_spec *spec,
>> +				struct hdmi_spec_per_pin *per_pin)
>> +{
>> +	int idx;
>> +
>> +	/* pcm already be attached to the pin */
>> +	if (per_pin->pcm)
>> +		return;
>> +	idx = hdmi_find_pcm_slot(spec, per_pin);
>> +	if (idx == -ENODEV)
>> +		return;
>> +	per_pin->pcm_idx = idx;
>> +	per_pin->pcm = spec->pcm_rec[idx];
>> +	set_bit(idx, &spec->pcm_bitmap);
>> +}
>> +
>> +static void hdmi_detach_hda_pcm(struct hdmi_spec *spec,
>> +				struct hdmi_spec_per_pin *per_pin)
>> +{
>> +	int idx;
>> +
>> +	/* pcm already be detached from the pin */
>> +	if (!per_pin->pcm)
>> +		return;
>> +	idx = per_pin->pcm_idx;
>> +	per_pin->pcm_idx = -1;
>> +	per_pin->pcm = NULL;
>> +	if (idx >= 0 && idx < spec->pcm_used)
>> +		clear_bit(idx, &spec->pcm_bitmap);
>> +}
>> +
>>   /* update ELD and jack state via audio component */
>>   static void sync_eld_via_acomp(struct hda_codec *codec,
>>   			       struct hdmi_spec_per_pin *per_pin)
>> @@ -1794,6 +1853,7 @@ static void sync_eld_via_acomp(struct hda_codec *codec,
>>   	struct hdmi_eld *eld = &spec->temp_eld;
>>   	int size;
>>
>> +	mutex_lock(&spec->pcm_lock);
>>   	mutex_lock(&per_pin->lock);
>>   	size = snd_hdac_acomp_get_eld(&codec->bus->core, per_pin->pin_nid,
>>   				      &eld->monitor_present, eld->eld_buffer,
>> @@ -1815,11 +1875,19 @@ static void sync_eld_via_acomp(struct hda_codec *codec,
>>   		eld->eld_size = 0;
>>   	}
>>
>> +	if (spec->dyn_pcm_assign) {
>> +		if (eld->eld_valid)
>> +			hdmi_attach_hda_pcm(spec, per_pin);
>> +		else
>> +			hdmi_detach_hda_pcm(spec, per_pin);
>> +	}
>> +
>>   	update_eld(codec, per_pin, eld);
>>   	snd_jack_report(per_pin->acomp_jack,
>>   			eld->monitor_present ? SND_JACK_AVOUT : 0);
>>    unlock:
>>   	mutex_unlock(&per_pin->lock);
>> +	mutex_unlock(&spec->pcm_lock);
>>   }
>>
>>   static bool hdmi_present_sense(struct hdmi_spec_per_pin *per_pin, int repoll)
>> @@ -1875,6 +1943,11 @@ static int hdmi_add_pin(struct hda_codec *codec, hda_nid_t pin_nid)
>>
>>   	per_pin->pin_nid = pin_nid;
>>   	per_pin->non_pcm = false;
>> +	if (spec->dyn_pcm_assign)
>> +		per_pin->pcm_idx = -1;
>> +	else
>> +		per_pin->pcm_idx = pin_idx;
>> +	per_pin->pin_nid_idx = pin_idx;
>>
>>   	err = hdmi_read_pin_conn(codec, pin_idx);
>>   	if (err < 0)
>> --
>> 1.9.1
>>