BUG: On output devices, snd_pcm_open() makes a nasty loud tick.

BUG: On output devices, snd_pcm_open() makes a nasty loud tick.

[Eric Toombs]

Minimal reproduction:

#include <alsa/asoundlib.h>
#include <stdbool.h>
int main(int argc, const char **argv)
{
    snd_pcm_t *out;
    assert(snd_pcm_open(&out,
                "default",
                SND_PCM_STREAM_PLAYBACK,
                false         // iff nonblocking stream
                ) == 0);
}

(Compile with gcc -o test test.c -lasound.)

Relevant lspci:

00:1f.3 Audio device: Intel Corporation Sunrise Point-LP HD Audio (rev 21)

uname:

Linux robert 6.13.8-arch1-1 #1 SMP PREEMPT_DYNAMIC Sun, 23 Mar 2025 17:17:30 +0000 x86_64 GNU/Linux

alsa-lib version: 1.2.13-1 (archlinux)

I've heard similar artefacts on many different sound cards, though, across many different architectures, always on linux.
One must wait about five minutes in between trials, or the artefact does not occur.

This isn't a minor detail.
The tick is very loud and very awful.
It might even damage speakers in a worst case scenario.

This started as [a bug in alsa-lib](https://github.com/alsa-project/alsa-lib/issues/451).
They say it's a kernel issue, though.
So, here I am.