[alsa-devel] [PATCH] ASoC: soc-pcm: do not hw_free BE if it's still used

[Qiao Zhou]

Do not free BE hw if it's still used by other FE during dpcm runtime
shutdown. Otherwise the BE runtime state will be STATE_HW_FREE and
won't be updated to STATE_CLOSE when shutdown ends, because BE dai
shutdown function won't close pcm when detecting BE is still under
use. With STATE_HW_FREE, BE can't be triggered start again.

This corner case can easily appear when one BE is used by two FE,
without this patch "ASoC: dpcm: Fix race between FE/BE updates and
trigger"(ea9d0d771fcd32cd56070819749477d511ec9117). One FE tries to
shutdown but it's raced against xrun on another FE. It improves the
be dai hw_free logic.

Signed-off-by: Qiao Zhou <zhouqiao at marvell.com>
---
 sound/soc/soc-pcm.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index 57277dd..70e8088 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -1664,6 +1664,10 @@ int dpcm_be_dai_hw_free(struct snd_soc_pcm_runtime *fe, int stream)
 		if (!snd_soc_dpcm_can_be_free_stop(fe, be, stream))
 				continue;
 
+		/* do not free hw if this BE is used by other FE */
+		if (be->dpcm[stream].users > 1)
+			continue;
+
 		if ((be->dpcm[stream].state != SND_SOC_DPCM_STATE_HW_PARAMS) &&
 		    (be->dpcm[stream].state != SND_SOC_DPCM_STATE_PREPARE) &&
 		    (be->dpcm[stream].state != SND_SOC_DPCM_STATE_HW_FREE) &&
-- 
1.7.9.5