From: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> [ Upstream commit 848aedfdc6ba25ad5652797db9266007773e44dd ] On start/pause_release/resume, when more than one FE is connected to the same BE, it's possible that the trigger is sent more than once. This is not desirable, we only want to trigger a BE once, which is straightforward to implement with a refcount. For stop/pause/suspend, the problem is more complicated: the check implemented in snd_soc_dpcm_can_be_free_stop() may fail due to a conceptual deadlock when we trigger the BE before the FE. In this case, the FE states have not yet changed, so there are corner cases where the TRIGGER_STOP is never sent - the dual case of start where multiple triggers might be sent. This patch suggests an unconditional trigger in all cases, without checking the FE states, using a refcount protected by the BE PCM stream lock. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> Reviewed-by: Kai Vehmanen <kai.vehmanen@xxxxxxxxxxxxxxx> Reviewed-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx> Reviewed-by: Ranjani Sridharan <ranjani.sridharan@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20211207173745.15850-6-pierre-louis.bossart@xxxxxxxxxxxxxxx Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- include/sound/soc-dpcm.h | 2 ++ sound/soc/soc-pcm.c | 53 +++++++++++++++++++++++++++++++--------- 2 files changed, 44 insertions(+), 11 deletions(-) diff --git a/include/sound/soc-dpcm.h b/include/sound/soc-dpcm.h index e296a3949b18b..d963f3b608489 100644 --- a/include/sound/soc-dpcm.h +++ b/include/sound/soc-dpcm.h @@ -101,6 +101,8 @@ struct snd_soc_dpcm_runtime { enum snd_soc_dpcm_state state; int trigger_pending; /* trigger cmd + 1 if pending, 0 if not */ + + int be_start; /* refcount protected by BE stream pcm lock */ }; #define for_each_dpcm_fe(be, stream, _dpcm) \ diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c index 7c7ae69f9410d..83977a715a61d 100644 --- a/sound/soc/soc-pcm.c +++ b/sound/soc/soc-pcm.c @@ -1630,7 +1630,7 @@ int dpcm_be_dai_startup(struct snd_soc_pcm_runtime *fe, int stream) be->dpcm[stream].state = SND_SOC_DPCM_STATE_CLOSE; goto unwind; } - + be->dpcm[stream].be_start = 0; be->dpcm[stream].state = SND_SOC_DPCM_STATE_OPEN; count++; } @@ -2120,14 +2120,21 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream, switch (cmd) { case SNDRV_PCM_TRIGGER_START: - if ((be->dpcm[stream].state != SND_SOC_DPCM_STATE_PREPARE) && + if (!be->dpcm[stream].be_start && + (be->dpcm[stream].state != SND_SOC_DPCM_STATE_PREPARE) && (be->dpcm[stream].state != SND_SOC_DPCM_STATE_STOP) && (be->dpcm[stream].state != SND_SOC_DPCM_STATE_PAUSED)) goto next; + be->dpcm[stream].be_start++; + if (be->dpcm[stream].be_start != 1) + goto next; + ret = soc_pcm_trigger(be_substream, cmd); - if (ret) + if (ret) { + be->dpcm[stream].be_start--; goto next; + } be->dpcm[stream].state = SND_SOC_DPCM_STATE_START; break; @@ -2135,9 +2142,15 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream, if ((be->dpcm[stream].state != SND_SOC_DPCM_STATE_SUSPEND)) goto next; + be->dpcm[stream].be_start++; + if (be->dpcm[stream].be_start != 1) + goto next; + ret = soc_pcm_trigger(be_substream, cmd); - if (ret) + if (ret) { + be->dpcm[stream].be_start--; goto next; + } be->dpcm[stream].state = SND_SOC_DPCM_STATE_START; break; @@ -2145,9 +2158,15 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream, if ((be->dpcm[stream].state != SND_SOC_DPCM_STATE_PAUSED)) goto next; + be->dpcm[stream].be_start++; + if (be->dpcm[stream].be_start != 1) + goto next; + ret = soc_pcm_trigger(be_substream, cmd); - if (ret) + if (ret) { + be->dpcm[stream].be_start--; goto next; + } be->dpcm[stream].state = SND_SOC_DPCM_STATE_START; break; @@ -2156,12 +2175,18 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream, (be->dpcm[stream].state != SND_SOC_DPCM_STATE_PAUSED)) goto next; - if (!snd_soc_dpcm_can_be_free_stop(fe, be, stream)) + if (be->dpcm[stream].state == SND_SOC_DPCM_STATE_START) + be->dpcm[stream].be_start--; + + if (be->dpcm[stream].be_start != 0) goto next; ret = soc_pcm_trigger(be_substream, cmd); - if (ret) + if (ret) { + if (be->dpcm[stream].state == SND_SOC_DPCM_STATE_START) + be->dpcm[stream].be_start++; goto next; + } be->dpcm[stream].state = SND_SOC_DPCM_STATE_STOP; break; @@ -2169,12 +2194,15 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream, if (be->dpcm[stream].state != SND_SOC_DPCM_STATE_START) goto next; - if (!snd_soc_dpcm_can_be_free_stop(fe, be, stream)) + be->dpcm[stream].be_start--; + if (be->dpcm[stream].be_start != 0) goto next; ret = soc_pcm_trigger(be_substream, cmd); - if (ret) + if (ret) { + be->dpcm[stream].be_start++; goto next; + } be->dpcm[stream].state = SND_SOC_DPCM_STATE_SUSPEND; break; @@ -2182,12 +2210,15 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream, if (be->dpcm[stream].state != SND_SOC_DPCM_STATE_START) goto next; - if (!snd_soc_dpcm_can_be_free_stop(fe, be, stream)) + be->dpcm[stream].be_start--; + if (be->dpcm[stream].be_start != 0) goto next; ret = soc_pcm_trigger(be_substream, cmd); - if (ret) + if (ret) { + be->dpcm[stream].be_start++; goto next; + } be->dpcm[stream].state = SND_SOC_DPCM_STATE_PAUSED; break; -- 2.39.2
