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_stream_unlock_irq – Unlock the PCM stream Synopsis void snd_pcm_stream_unlock_irq(struct snd_pcm_substream *substream); Arguments substream PCM substream Description This is a counter-part of snd_pcm_stream_lock_irq. Copyright
snd_pcm_stream_unlock – Unlock the PCM stream Synopsis void snd_pcm_stream_unlock(struct snd_pcm_substream *substream); Arguments substream PCM substream Description This unlocks the PCM stream that has been locked via snd_pcm_stream_lock. Copyright
snd_pcm_stream_str – Get a string naming the direction of a stream Synopsis const char *snd_pcm_stream_str(struct snd_pcm_substream *substream); Arguments substream the pcm substream instance Return A string naming the direction of the stream. Copyright
snd_pcm_stream_lock_irqsave – Lock the PCM stream Synopsis snd_pcm_stream_lock_irqsave(substream, flags); Arguments substream PCM substream flags irq flags Description This locks the PCM stream like snd_pcm_stream_lock but with the local IRQ (only when nonatomic is false). In nonatomic case, this is identical as snd_pcm_stream_lock. Copyright
snd_pcm_stream_lock_irq – Lock the PCM stream Synopsis void snd_pcm_stream_lock_irq(struct snd_pcm_substream *substream); Arguments substream PCM substream Description This locks the PCM stream like snd_pcm_stream_lock and disables the local IRQ (only when nonatomic is false). In nonatomic case, this is identical as snd_pcm_stream_lock. Copyright
snd_pcm_stream_lock – Lock the PCM stream Synopsis void snd_pcm_stream_lock(struct snd_pcm_substream *substream); Arguments substream PCM substream Description This locks the PCM stream’s spinlock or mutex depending on the nonatomic flag of the given substream. This also takes the global link rw lock (or rw sem), too, for avoiding the race with linked streams. Copyright
snd_pcm_stream_linked – Check whether the substream is linked with others Synopsis int snd_pcm_stream_linked(struct snd_pcm_substream *substream); Arguments substream substream to check Description Returns true if the given substream is being linked with others. Copyright
snd_pcm_stop_xrun – stop the running streams as XRUN Synopsis int snd_pcm_stop_xrun(struct snd_pcm_substream *substream); Arguments substream the PCM substream instance Description This stops the given running substream (and all linked substreams) as XRUN. Unlike snd_pcm_stop, this function takes the substream lock by itself. Return Zero if successful, or a negative error code. Copyright
snd_pcm_stop – try to stop all running streams in the substream group Synopsis int snd_pcm_stop(struct snd_pcm_substream *substream, snd_pcm_state_t state); Arguments substream the PCM substream instance state PCM state after stopping the stream Description The state of each stream is then changed to the given state unconditionally. Return Zero if successful, or a negative error code….
snd_pcm_sgbuf_ops_page – get the page struct at the given offset Synopsis struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigned long offset); Arguments substream the pcm substream instance offset the buffer offset Description Used as the page callback of PCM ops. Return The page struct at the given buffer offset. NULL on failure. Copyright
snd_pcm_sgbuf_get_ptr – Get the virtual address at the corresponding offset Synopsis void *snd_pcm_sgbuf_get_ptr(struct snd_pcm_substream *substream, unsigned int ofs); Arguments substream PCM substream ofs byte offset Copyright
snd_pcm_sgbuf_get_chunk_size – Compute the max size that fits within the contig. page from the given size Synopsis unsigned int snd_pcm_sgbuf_get_chunk_size(struct snd_pcm_substream *substream, unsigned int ofs, unsigned int size); Arguments substream PCM substream ofs byte offset size byte size to examine Copyright
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…