From 62ba568f7aef4beb0eda945a2b2a91b7a2b8f215 Mon Sep 17 00:00:00 2001
From: Ricardo Biehl Pasquali <pasqualirb@gmail.com>
Date: Sat, 25 Aug 2018 16:53:23 -0300
Subject: [PATCH] ALSA: pcm: Return 0 when size < start_threshold in capture
Git-commit: 62ba568f7aef4beb0eda945a2b2a91b7a2b8f215
Patch-mainline: v4.20-rc1
References: bsc#1121278

In __snd_pcm_lib_xfer(), when capture, if state is PREPARED
and size is less than start_threshold nothing can be done.
As there is no error, 0 is returned.

Signed-off-by: Ricardo Biehl Pasquali <pasqualirb@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

---
 sound/core/pcm_lib.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 4e6110d778bd..7f71c2449af5 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -2173,11 +2173,16 @@ snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream,
 		goto _end_unlock;
 
 	if (!is_playback &&
-	    runtime->status->state == SNDRV_PCM_STATE_PREPARED &&
-	    size >= runtime->start_threshold) {
-		err = snd_pcm_start(substream);
-		if (err < 0)
+	    runtime->status->state == SNDRV_PCM_STATE_PREPARED) {
+		if (size >= runtime->start_threshold) {
+			err = snd_pcm_start(substream);
+			if (err < 0)
+				goto _end_unlock;
+		} else {
+			/* nothing to do */
+			err = 0;
 			goto _end_unlock;
+		}
 	}
 
 	runtime->twake = runtime->control->avail_min ? : 1;
-- 
2.20.1