linux-kernel - [PATCH 3.16 04/83] ALSA: compress: Fix regression on compressed capture streams

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Date:   Wed, 20 Nov 2019 15:37:14 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, Denis Kirjanov <kda@...ux-powerpc.org>,
        "Charles Keepax" <ckeepax@...nsource.cirrus.com>,
        "Takashi Iwai" <tiwai@...e.de>, "Vinod Koul" <vkoul@...nel.org>
Subject: [PATCH 3.16 04/83] ALSA: compress: Fix regression on compressed
 capture streams

3.16.78-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Charles Keepax <ckeepax@...nsource.cirrus.com>

commit 4475f8c4ab7b248991a60d9c02808dbb813d6be8 upstream.

A previous fix to the stop handling on compressed capture streams causes
some knock on issues. The previous fix updated snd_compr_drain_notify to
set the state back to PREPARED for capture streams. This causes some
issues however as the handling for snd_compr_poll differs between the
two states and some user-space applications were relying on the poll
failing after the stream had been stopped.

To correct this regression whilst still fixing the original problem the
patch was addressing, update the capture handling to skip the PREPARED
state rather than skipping the SETUP state as it has done until now.

Fixes: 4f2ab5e1d13d ("ALSA: compress: Fix stop handling on compressed capture streams")
Signed-off-by: Charles Keepax <ckeepax@...nsource.cirrus.com>
Acked-by: Vinod Koul <vkoul@...nel.org>
Signed-off-by: Takashi Iwai <tiwai@...e.de>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 include/sound/compress_driver.h |  5 +----
 sound/core/compress_offload.c   | 16 +++++++++++-----
 2 files changed, 12 insertions(+), 9 deletions(-)

--- a/include/sound/compress_driver.h
+++ b/include/sound/compress_driver.h
@@ -176,10 +176,7 @@ static inline void snd_compr_drain_notif
 	if (snd_BUG_ON(!stream))
 		return;
 
-	if (stream->direction == SND_COMPRESS_PLAYBACK)
-		stream->runtime->state = SNDRV_PCM_STATE_SETUP;
-	else
-		stream->runtime->state = SNDRV_PCM_STATE_PREPARED;
+	stream->runtime->state = SNDRV_PCM_STATE_SETUP;
 
 	wake_up(&stream->runtime->sleep);
 }
--- a/sound/core/compress_offload.c
+++ b/sound/core/compress_offload.c
@@ -549,10 +549,7 @@ snd_compr_set_params(struct snd_compr_st
 		stream->metadata_set = false;
 		stream->next_track = false;
 
-		if (stream->direction == SND_COMPRESS_PLAYBACK)
-			stream->runtime->state = SNDRV_PCM_STATE_SETUP;
-		else
-			stream->runtime->state = SNDRV_PCM_STATE_PREPARED;
+		stream->runtime->state = SNDRV_PCM_STATE_SETUP;
 	} else {
 		return -EPERM;
 	}
@@ -668,8 +665,17 @@ static int snd_compr_start(struct snd_co
 {
 	int retval;
 
-	if (stream->runtime->state != SNDRV_PCM_STATE_PREPARED)
+	switch (stream->runtime->state) {
+	case SNDRV_PCM_STATE_SETUP:
+		if (stream->direction != SND_COMPRESS_CAPTURE)
+			return -EPERM;
+		break;
+	case SNDRV_PCM_STATE_PREPARED:
+		break;
+	default:
 		return -EPERM;
+	}
+
 	retval = stream->ops->trigger(stream, SNDRV_PCM_TRIGGER_START);
 	if (!retval)
 		stream->runtime->state = SNDRV_PCM_STATE_RUNNING;