snd_pcm_set_runtime_buffer(9)

💖 snd_pcm_set_runtime_buffer(9) 💖

okay bestie, welcome to the Kernel API Manual ✨ — this is the page for snd_pcm_set_runtime_buffer, and it's honestly the coziest little helper in the whole PCM saga. let's get into it 🎀

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🌸 NAME 🌸

snd_pcm_set_runtime_buffer — Set the PCM runtime buffer 💅

like… that's it. that's the job. setting the PCM runtime buffer. iconic behavior fr fr.

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✨ SYNOPSIS ✨

void snd_pcm_set_runtime_buffer (struct snd_pcm_substream *substream ,
struct snd_dma_buffer *bufp );

two args, one job, zero drama 🫶

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🦋 ARGUMENTS 🦋

• substream — the PCM substream you're setting. this is the main character here, the one getting the glow-up ✨
• bufp — the buffer information. and listen: if you pass NULL here, it clears instead of sets. so NULL is not a bug, it's a feature, it's the "nvm forget it" button 🙈

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👑 DESCRIPTION 👑

so here's the whole vibe, no cap:

when bufp is non-NULL, this function copies the buffer information over to runtime->dma_buffer. that's the whole thing — copy, done, slay 💅

but when bufp is not non-NULL (aka when it is NULL, bestie, keep up 💀), it clears the current buffer information instead. so it's like:

• bufp = actual buffer info → copy it into runtime->dma_buffer 🍓
• bufp = NULL → wipe the current buffer info, we're done here 🧹

and that's literally the entire function. small, focused, does one thing well. main character energy honestly 👑

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🌈 SEE ALSO 🌈

okay this is the part where I hold your hand and walk you through the whole friend group, because snd_pcm_set_runtime_buffer rolls DEEP. the kernel file living at ./include/sound/pcm.h is the hangout spot 🏠 and here's everyone:

• snd_pcm_stream_linked(9)
• snd_pcm_stream_lock_irqsave(9)
• snd_pcm_stream_lock_irqsave_nested(9)
• snd_pcm_group_for_each_entry(9)
• snd_pcm_running(9)
• __snd_pcm_set_state(9)
• bytes_to_samples(9)
• bytes_to_frames(9)
• samples_to_bytes(9)
• frames_to_bytes(9)
• frame_aligned(9)
• snd_pcm_lib_buffer_bytes(9)
• snd_pcm_lib_period_bytes(9)
• snd_pcm_playback_avail(9)
• snd_pcm_capture_avail(9)
• snd_pcm_playback_hw_avail(9)
• snd_pcm_capture_hw_avail(9)
• snd_pcm_playback_ready(9)
• snd_pcm_capture_ready(9)
• snd_pcm_playback_data(9)
• snd_pcm_playback_empty(9)
• snd_pcm_capture_empty(9)
• snd_pcm_trigger_done(9)
• params_channels(9)
• params_rate(9)
• params_period_size(9)
• params_periods(9)
• params_buffer_size(9)
• params_buffer_bytes(9)
• snd_pcm_hw_constraint_single(9)
• snd_pcm_format_cpu_endian(9)
• snd_pcm_set_sync(9)
• snd_pcm_gettime(9)
• snd_pcm_set_fixed_buffer(9)
• snd_pcm_set_fixed_buffer_all(9)
• snd_pcm_sgbuf_get_addr(9)
• snd_pcm_sgbuf_get_chunk_size(9)
• snd_pcm_limit_isa_dma_size(9)
• snd_pcm_direction_name(9)
• snd_pcm_stream_str(9)
• snd_pcm_chmap_substream(9)
• pcm_format_to_bits(9)
• pcm_for_each_format(9)

like I said. deep bench. go read them, they're all worth it, iykyk 💜

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okay that's the page bestie!! 🎀 this one comes to you straight from the source file ./include/sound, stamped October 2026 — so go forth, set those runtime buffers, clear them when you must, and remember: NULL is a valid lifestyle choice 🦋💖 periodt ✨