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DPCM can update the FE/BE connection states totally asynchronously from the FE's PCM state. Most of FE/BE state changes are protected by mutex, so that they won't race, but there are still some actions that are uncovered. For example, suppose to switch a BE while a FE's stream is running. This would call soc_dpcm_runtime_update(), which sets FE's runtime_update flag, then sets up and starts BEs, and clears FE's runtime_update flag again. When a device emits XRUN during this operation, the PCM core triggers snd_pcm_stop(XRUN). Since the trigger action is an atomic ops, this isn't blocked by the mutex, thus it kicks off DPCM's trigger action. It eventually updates and clears FE's runtime_update flag while soc_dpcm_runtime_update() is running concurrently, and it results in confusion. Usually, for avoiding such a race, we take a lock. There is a PCM stream lock for that purpose. However, as already mentioned, the trigger action is atomic, and we can't take the lock for the whole soc_dpcm_runtime_update() or other operations that include the lengthy jobs like hw_params or prepare. This patch provides an alternative solution. This adds a way to defer the conflicting trigger callback to be executed at the end of FE/BE state changes. For doing it, two things are introduced: - Each runtime_update state change of FEs is protected via PCM stream lock. - The FE's trigger callback checks the runtime_update flag. If it's not set, the trigger action is executed there. If set, mark the pending trigger action and returns immediately. - At the exit of runtime_update state change, it checks whether the pending trigger is present. If yes, it executes the trigger action at this point. Reported-and-tested-by: Qiao Zhou <zhouqiao@marvell.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Acked-by: Liam Girdwood <liam.r.girdwood@linux.intel.com> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org
163 lines
4.7 KiB
C
163 lines
4.7 KiB
C
/*
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* linux/sound/soc-dpcm.h -- ALSA SoC Dynamic PCM Support
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*
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* Author: Liam Girdwood <lrg@ti.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef __LINUX_SND_SOC_DPCM_H
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#define __LINUX_SND_SOC_DPCM_H
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#include <linux/slab.h>
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#include <linux/list.h>
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#include <sound/pcm.h>
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struct snd_soc_pcm_runtime;
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/*
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* Types of runtime_update to perform. e.g. originated from FE PCM ops
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* or audio route changes triggered by muxes/mixers.
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*/
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enum snd_soc_dpcm_update {
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SND_SOC_DPCM_UPDATE_NO = 0,
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SND_SOC_DPCM_UPDATE_BE,
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SND_SOC_DPCM_UPDATE_FE,
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};
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/*
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* Dynamic PCM Frontend -> Backend link management states.
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*/
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enum snd_soc_dpcm_link_state {
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SND_SOC_DPCM_LINK_STATE_NEW = 0, /* newly created link */
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SND_SOC_DPCM_LINK_STATE_FREE, /* link to be dismantled */
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};
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/*
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* Dynamic PCM Frontend -> Backend link PCM states.
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*/
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enum snd_soc_dpcm_state {
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SND_SOC_DPCM_STATE_NEW = 0,
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SND_SOC_DPCM_STATE_OPEN,
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SND_SOC_DPCM_STATE_HW_PARAMS,
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SND_SOC_DPCM_STATE_PREPARE,
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SND_SOC_DPCM_STATE_START,
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SND_SOC_DPCM_STATE_STOP,
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SND_SOC_DPCM_STATE_PAUSED,
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SND_SOC_DPCM_STATE_SUSPEND,
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SND_SOC_DPCM_STATE_HW_FREE,
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SND_SOC_DPCM_STATE_CLOSE,
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};
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/*
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* Dynamic PCM trigger ordering. Triggering flexibility is required as some
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* DSPs require triggering before/after their CPU platform and DAIs.
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*
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* i.e. some clients may want to manually order this call in their PCM
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* trigger() whilst others will just use the regular core ordering.
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*/
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enum snd_soc_dpcm_trigger {
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SND_SOC_DPCM_TRIGGER_PRE = 0,
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SND_SOC_DPCM_TRIGGER_POST,
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SND_SOC_DPCM_TRIGGER_BESPOKE,
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};
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/*
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* Dynamic PCM link
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* This links together a FE and BE DAI at runtime and stores the link
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* state information and the hw_params configuration.
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*/
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struct snd_soc_dpcm {
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/* FE and BE DAIs*/
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struct snd_soc_pcm_runtime *be;
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struct snd_soc_pcm_runtime *fe;
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/* link state */
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enum snd_soc_dpcm_link_state state;
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/* list of BE and FE for this DPCM link */
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struct list_head list_be;
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struct list_head list_fe;
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/* hw params for this link - may be different for each link */
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struct snd_pcm_hw_params hw_params;
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#ifdef CONFIG_DEBUG_FS
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struct dentry *debugfs_state;
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#endif
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};
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/*
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* Dynamic PCM runtime data.
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*/
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struct snd_soc_dpcm_runtime {
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struct list_head be_clients;
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struct list_head fe_clients;
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int users;
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struct snd_pcm_runtime *runtime;
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struct snd_pcm_hw_params hw_params;
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/* state and update */
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enum snd_soc_dpcm_update runtime_update;
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enum snd_soc_dpcm_state state;
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int trigger_pending; /* trigger cmd + 1 if pending, 0 if not */
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};
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/* can this BE stop and free */
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int snd_soc_dpcm_can_be_free_stop(struct snd_soc_pcm_runtime *fe,
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struct snd_soc_pcm_runtime *be, int stream);
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/* can this BE perform a hw_params() */
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int snd_soc_dpcm_can_be_params(struct snd_soc_pcm_runtime *fe,
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struct snd_soc_pcm_runtime *be, int stream);
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/* is the current PCM operation for this FE ? */
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int snd_soc_dpcm_fe_can_update(struct snd_soc_pcm_runtime *fe, int stream);
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/* is the current PCM operation for this BE ? */
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int snd_soc_dpcm_be_can_update(struct snd_soc_pcm_runtime *fe,
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struct snd_soc_pcm_runtime *be, int stream);
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/* get the substream for this BE */
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struct snd_pcm_substream *
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snd_soc_dpcm_get_substream(struct snd_soc_pcm_runtime *be, int stream);
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/* get the BE runtime state */
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enum snd_soc_dpcm_state
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snd_soc_dpcm_be_get_state(struct snd_soc_pcm_runtime *be, int stream);
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/* set the BE runtime state */
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void snd_soc_dpcm_be_set_state(struct snd_soc_pcm_runtime *be, int stream,
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enum snd_soc_dpcm_state state);
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/* internal use only */
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int soc_dpcm_be_digital_mute(struct snd_soc_pcm_runtime *fe, int mute);
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int soc_dpcm_debugfs_add(struct snd_soc_pcm_runtime *rtd);
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int soc_dpcm_runtime_update(struct snd_soc_card *);
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int dpcm_path_get(struct snd_soc_pcm_runtime *fe,
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int stream, struct snd_soc_dapm_widget_list **list_);
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int dpcm_process_paths(struct snd_soc_pcm_runtime *fe,
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int stream, struct snd_soc_dapm_widget_list **list, int new);
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int dpcm_be_dai_startup(struct snd_soc_pcm_runtime *fe, int stream);
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int dpcm_be_dai_shutdown(struct snd_soc_pcm_runtime *fe, int stream);
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void dpcm_be_disconnect(struct snd_soc_pcm_runtime *fe, int stream);
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void dpcm_clear_pending_state(struct snd_soc_pcm_runtime *fe, int stream);
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int dpcm_be_dai_hw_free(struct snd_soc_pcm_runtime *fe, int stream);
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int dpcm_be_dai_hw_params(struct snd_soc_pcm_runtime *fe, int tream);
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int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream, int cmd);
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int dpcm_be_dai_prepare(struct snd_soc_pcm_runtime *fe, int stream);
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int dpcm_dapm_stream_event(struct snd_soc_pcm_runtime *fe, int dir,
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int event);
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static inline void dpcm_path_put(struct snd_soc_dapm_widget_list **list)
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{
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kfree(*list);
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}
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#endif
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