From bf1ad3e007e26df838e839bba97c3396ee91f51d Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Tue, 4 Sep 2018 17:58:38 +0200
Subject: [PATCH] staging: bcm2835-audio: Fix incorrect draining handling
Git-commit: bf1ad3e007e26df838e839bba97c3396ee91f51d
Patch-mainline: v4.20-rc1
References: FATE#324827

The handling of SNDRV_PCM_TRIGGER_STOP at the trigger callback is
Incorrect: when the STOP is issued, the driver is supposed to drop the
stream immediately.  Meanwhile bcm2835 driver checks the DRAINING
state and tries to issue some different command.

This patch straightens things a bit, dropping the incorrect state
checks.  The draining behavior would be still not perfect at this
point, but will be improved in a later patch.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c |   18 ++++----------
 1 file changed, 6 insertions(+), 12 deletions(-)

--- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
+++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
@@ -153,7 +153,6 @@ static int snd_bcm2835_playback_open_gen
 	chip->alsa_stream[idx] = alsa_stream;
 
 	chip->opened |= (1 << idx);
-	alsa_stream->draining = 1;
 
 out:
 	mutex_unlock(&chip->audio_mutex);
@@ -268,6 +267,7 @@ static int snd_bcm2835_pcm_prepare(struc
 	alsa_stream->buffer_size = snd_pcm_lib_buffer_bytes(substream);
 	alsa_stream->period_size = snd_pcm_lib_period_bytes(substream);
 	alsa_stream->pos = 0;
+	alsa_stream->draining = false;
 
 	audio_debug("buffer_size=%d, period_size=%d pos=%d frame_bits=%d\n",
 		alsa_stream->buffer_size, alsa_stream->period_size,
@@ -312,21 +312,15 @@ static int snd_bcm2835_pcm_trigger(struc
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 		err = bcm2835_audio_start(alsa_stream);
-		if (!err)
-			alsa_stream->draining = 1;
-		else
+		if (err)
 			audio_error(" Failed to START alsa device (%d)\n", err);
 		break;
+	case SNDRV_PCM_TRIGGER_DRAIN:
+		alsa_stream->draining = true;
+		break;
 	case SNDRV_PCM_TRIGGER_STOP:
-		if (runtime->status->state == SNDRV_PCM_STATE_DRAINING) {
-			audio_info("DRAINING\n");
-			alsa_stream->draining = 1;
-		} else {
-			audio_info("DROPPING\n");
-			alsa_stream->draining = 0;
-		}
 		err = bcm2835_audio_stop(alsa_stream);
-		if (err != 0)
+		if (err)
 			audio_error(" Failed to STOP alsa device (%d)\n", err);
 		break;
 	default: