ALSA: dice: share PCM buffer size for both direction

This commit allows ALSA dice driver to share PCM buffer size for both
capture and playback PCM substream. When AMDTP domain starts for one
of the PCM substream, buffer size of the PCM substream is stores to
AMDTP domain structure. Some AMDTP streams have already run with the
buffer size when another PCM substream starts, therefore the PCM
substream has a constraint to its buffer size.

Signed-off-by: Takashi Sakamoto <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Takashi Iwai <[e-mail]>

sound/firewire/dice/dice-midi.c

···
 
 	mutex_lock(&dice->mutex);
 
-	err = snd_dice_stream_reserve_duplex(dice, 0, 0);
+	err = snd_dice_stream_reserve_duplex(dice, 0, 0, 0);
 	if (err >= 0) {
 		++dice->substreams_counter;
 		err = snd_dice_stream_start_duplex(dice);

sound/firewire/dice/dice-pcm.c

···
 	if (!internal ||
 	    (dice->substreams_counter > 0 && d->events_per_period > 0)) {
 		unsigned int frames_per_period = d->events_per_period;
+		unsigned int frames_per_buffer = d->events_per_buffer;
 		unsigned int rate;
 
 		err = snd_dice_transaction_get_rate(dice, &rate);
···
 
 		if (frames_per_period > 0) {
 			// For double_pcm_frame quirk.
-			if (rate > 96000)
+			if (rate > 96000) {
 				frames_per_period *= 2;
+				frames_per_buffer *= 2;
+			}
 
 			err = snd_pcm_hw_constraint_minmax(substream->runtime,
 					SNDRV_PCM_HW_PARAM_PERIOD_SIZE,
 					frames_per_period, frames_per_period);
+			if (err < 0) {
+				mutex_unlock(&dice->mutex);
+				goto err_locked;
+			}
+
+			err = snd_pcm_hw_constraint_minmax(substream->runtime,
+					SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
+					frames_per_buffer, frames_per_buffer);
 			if (err < 0) {
 				mutex_unlock(&dice->mutex);
 				goto err_locked;
···
 	if (substream->runtime->status->state == SNDRV_PCM_STATE_OPEN) {
 		unsigned int rate = params_rate(hw_params);
 		unsigned int events_per_period = params_period_size(hw_params);
+		unsigned int events_per_buffer = params_buffer_size(hw_params);
 
 		mutex_lock(&dice->mutex);
 		// For double_pcm_frame quirk.
-		if (rate > 96000)
+		if (rate > 96000) {
 			events_per_period /= 2;
+			events_per_buffer /= 2;
+		}
 		err = snd_dice_stream_reserve_duplex(dice, rate,
-						     events_per_period);
+					events_per_period, events_per_buffer);
 		if (err >= 0)
 			++dice->substreams_counter;
 		mutex_unlock(&dice->mutex);

sound/firewire/dice/dice-stream.c

···
 }
 
 int snd_dice_stream_reserve_duplex(struct snd_dice *dice, unsigned int rate,
-				   unsigned int events_per_period)
+				   unsigned int events_per_period,
+				   unsigned int events_per_buffer)
 {
 	unsigned int curr_rate;
 	int err;
···
 			goto error;
 
 		err = amdtp_domain_set_events_per_period(&dice->domain,
-							 events_per_period, 0);
+					events_per_period, events_per_buffer);
 		if (err < 0)
 			goto error;
 	}

sound/firewire/dice/dice.h

···
 int snd_dice_stream_init_duplex(struct snd_dice *dice);
 void snd_dice_stream_destroy_duplex(struct snd_dice *dice);
 int snd_dice_stream_reserve_duplex(struct snd_dice *dice, unsigned int rate,
-				   unsigned int events_per_period);
+				   unsigned int events_per_period,
+				   unsigned int events_per_buffer);
 void snd_dice_stream_update_duplex(struct snd_dice *dice);
 int snd_dice_stream_detect_current_formats(struct snd_dice *dice);