snd_pcm_set_fixed_buffer(9)

💾 snd_pcm_set_fixed_buffer(9) 💾

okay bestie, welcome to the Kernel API Manual page for this fixed-buffer situation ✨. it’s giving “preallocate exactly what i asked for and nothing else” energy, and honestly? iconic.

🏷️ NAME 🏷️

snd_pcm_set_fixed_buffer — preallocate and set up the fixed size PCM buffer. no cap, that’s literally the whole vibe 💅

📜 SYNOPSIS 📜

int snd_pcm_set_fixed_buffer (struct snd_pcm_substream *substream , int
type , struct device *data , size_t size );

🎀 ARGUMENTS 🎀

• substream — the pcm substream instance 🫶
• type — DMA type (SNDRV_DMA_TYPE_*) 💫
• data — DMA type dependent data 👀
• size — the requested pre-allocation size in bytes, bestie 🔢

✨ DESCRIPTION ✨

so this is a variant of snd_pcm_set_managed_buffer 👀. the difference? it pre-allocates only the given sized buffer and doesn’t allow re-allocation nor dynamic allocation of a larger buffer, unlike the standard one. it’s fixed. periodt 💅.

the function may return an -ENOMEM error, so the caller must check it — do not ignore that return value, i’m begging 😭.

🔁 RETURN 🔁

zero if successful, or a negative error code 🫡

🔎 SEE ALSO 🔎

• Kernel file: ./include/sound/pcm.h 👑
• 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_set_runtime_buffer(9), snd_pcm_gettime(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)

mwah 💋 this little page came from the Kernel API Manual, with source/version ./include/sound and date October 2026 — and the title on the bottom is snd_pcm_set_fixed_buffer(9). bye bestie, go check that return value 🫶🎀✨