The Linux Manuals (man pages) document is an important part of Linux documents. Linux Manuals are organized as several sections. Each section has a group of commands for a specific area in Linux usage, administration or development.
snd_pcm_sgbuf_get_addr – Get the DMA address at the corresponding offset Synopsis dma_addr_t snd_pcm_sgbuf_get_addr(struct snd_pcm_substream * substream, unsigned int ofs); Arguments substream PCM substream ofs byte offset Copyright
snd_pcm_set_sync – set the PCM sync id Synopsis void snd_pcm_set_sync(struct snd_pcm_substream *substream); Arguments substream the pcm substream Description Sets the PCM sync identifier for the card. Copyright
snd_pcm_set_runtime_buffer – Set the PCM runtime buffer Synopsis void snd_pcm_set_runtime_buffer(struct snd_pcm_substream *substream, struct snd_dma_buffer *bufp); Arguments substream PCM substream to set bufp the buffer information, NULL to clear Description Copy the buffer information to runtime->dma_buffer when bufp is non-NULL. Otherwise it clears the current buffer information. Copyright
snd_pcm_set_ops – set the PCM operators Synopsis void snd_pcm_set_ops(struct snd_pcm *pcm, int direction, const struct snd_pcm_ops *ops); Arguments pcm the pcm instance direction stream direction, SNDRV_PCM_STREAM_XXX ops the operator table Description Sets the given PCM operators to the pcm instance. Copyright
snd_pcm_running – Check whether the substream is in a running state Synopsis int snd_pcm_running(struct snd_pcm_substream *substream); Arguments substream substream to check Description Returns true if the given substream is in the state RUNNING, or in the state DRAINING for playback. Copyright
snd_pcm_rate_to_rate_bit – converts sample rate to SNDRV_PCM_RATE_xxx bit Synopsis unsigned int snd_pcm_rate_to_rate_bit(unsigned int rate); Arguments rate the sample rate to convert Return The SNDRV_PCM_RATE_xxx flag that corresponds to the given rate, or SNDRV_PCM_RATE_KNOT for an unknown rate. Copyright
snd_pcm_rate_range_to_bits – converts rate range to SNDRV_PCM_RATE_xxx bit Synopsis unsigned int snd_pcm_rate_range_to_bits(unsigned int rate_min, unsigned int rate_max); Arguments rate_min the minimum sample rate rate_max the maximum sample rate Description This function has an implicit assumption: the rates in the given range have only the pre-defined rates like 44100 or 16000. Return The SNDRV_PCM_RATE_xxx flag that…
snd_pcm_rate_mask_intersect – computes the intersection between two rate masks Synopsis unsigned int snd_pcm_rate_mask_intersect(unsigned int rates_a, unsigned int rates_b); Arguments rates_a The first rate mask rates_b The second rate mask Description This function computes the rates that are supported by both rate masks passed to the function. It will take care of the special handling of…
snd_pcm_rate_bit_to_rate – converts SNDRV_PCM_RATE_xxx bit to sample rate Synopsis unsigned int snd_pcm_rate_bit_to_rate(unsigned int rate_bit); Arguments rate_bit the rate bit to convert Return The sample rate that corresponds to the given SNDRV_PCM_RATE_xxx flag or 0 for an unknown rate bit. Copyright
snd_pcm_playback_ready – check whether the playback buffer is available Synopsis int snd_pcm_playback_ready(struct snd_pcm_substream *substream); Arguments substream the pcm substream instance Description Checks whether enough free space is available on the playback buffer. Return Non-zero if available, or zero if not. Copyright
snd_pcm_playback_hw_avail – Get the queued space for playback Synopsis snd_pcm_sframes_t snd_pcm_playback_hw_avail(struct snd_pcm_runtime * runtime); Arguments runtime PCM runtime instance Copyright
snd_pcm_playback_empty – check whether the playback buffer is empty Synopsis int snd_pcm_playback_empty(struct snd_pcm_substream *substream); Arguments substream the pcm substream instance Description Checks whether the playback buffer is empty. Return Non-zero if empty, or zero if not. Copyright
snd_pcm_playback_data – check whether any data exists on the playback buffer Synopsis int snd_pcm_playback_data(struct snd_pcm_substream *substream); Arguments substream the pcm substream instance Description Checks whether any data exists on the playback buffer. Return Non-zero if any data exists, or zero if not. If stop_threshold is bigger or equal to boundary, then this function returns always…
snd_pcm_playback_avail – Get the available (writable) space for playback Synopsis snd_pcm_uframes_t snd_pcm_playback_avail(struct snd_pcm_runtime * runtime); Arguments runtime PCM runtime instance Description Result is between 0 … (boundary – 1) Copyright
snd_pcm_period_elapsed – update the pcm status for the next period Synopsis void snd_pcm_period_elapsed(struct snd_pcm_substream *substream); Arguments substream the pcm substream instance Description This function is called from the interrupt handler when the PCM has processed the period size. It will update the current pointer, wake up sleepers, etc. Even if more than one periods have…
snd_pcm_notify – Add/remove the notify list Synopsis int snd_pcm_notify(struct snd_pcm_notify *notify, int nfree); Arguments notify PCM notify list nfree 0 = register, 1 = unregister Description This adds the given notifier to the global list so that the callback is called for each registered PCM devices. This exists only for PCM OSS emulation, so far….
snd_pcm_new_stream – create a new PCM stream Synopsis int snd_pcm_new_stream(struct snd_pcm *pcm, int stream, int substream_count); Arguments pcm the pcm instance stream the stream direction, SNDRV_PCM_STREAM_XXX substream_count the number of substreams Description Creates a new stream for the pcm. The corresponding stream on the pcm must have been empty before calling this, i.e. zero must…
snd_pcm_new_internal – create a new internal PCM instance Synopsis int snd_pcm_new_internal(struct snd_card *card, const char *id, int device, int playback_count, int capture_count, struct snd_pcm **rpcm); Arguments card the card instance id the id string device the device index (zero based – shared with normal PCMs) playback_count the number of substreams for playback capture_count the number…
snd_pcm_new – create a new PCM instance Synopsis int snd_pcm_new(struct snd_card *card, const char *id, int device, int playback_count, int capture_count, struct snd_pcm **rpcm); Arguments card the card instance id the id string device the device index (zero based) playback_count the number of substreams for playback capture_count the number of substreams for capture rpcm the…
snd_pcm_mmap_data_open – increase the mmap counter Synopsis void snd_pcm_mmap_data_open(struct vm_area_struct *area); Arguments area VMA Description PCM mmap callback should handle this counter properly Copyright