alsa rpi bug test tool

alsa-playback.c

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <math.h>
#include <time.h>
#include <alsa/asoundlib.h>

#define BUFSIZE 1024
#define PI 3.141592654

int main (int argc, char *argv[])
{
    snd_pcm_hw_params_t *hw_params;
    snd_pcm_t *playback_handle;
    unsigned int rate = 48000;
    double frequency = 750.0;
    unsigned int channels;
    unsigned int buffer_time;
    int iters;
    int16_t *buf;
    int dir = 0;
    int err;
    int i;

    if(argc < 2) {
        printf("alsa-playback device rate frequency\n");
        exit(1);
    }

    if(argc > 2)
        rate = atoi(argv[2]);

    if(argc > 3)
        frequency = atof(argv[3]);

    printf("rate: %u -- frequency: %lf\n", rate, frequency);
    iters = rate / (BUFSIZE / 10);

    if ((err = snd_pcm_open (&playback_handle, argv[1], SND_PCM_STREAM_PLAYBACK, 0)) < 0) {
        fprintf(stderr, "cannot open audio device %s (%s)\n", argv[1],
                snd_strerror(err));
        exit(1);
    }

    if((err = snd_pcm_hw_params_malloc(&hw_params)) < 0) {
        fprintf(stderr, "cannot allocate hardware parameter structure (%s)\n",
                snd_strerror(err));
        exit(1);
    }

    if ((err = snd_pcm_hw_params_any(playback_handle, hw_params)) < 0) {
        fprintf(stderr, "cannot initia	lize hardware parameter structure (%s)\n",
                snd_strerror(err));
        exit(1);
    }

    if ((err = snd_pcm_hw_params_set_access (playback_handle, hw_params,
                    SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
        fprintf(stderr, "cannot set access type (%s)\n",
                snd_strerror(err));
        exit(1);
    }

    if ((err = snd_pcm_hw_params_set_format (playback_handle, hw_params,
                    SND_PCM_FORMAT_S16_LE)) < 0) {
        fprintf(stderr, "cannot set sample format (%s)\n",
                snd_strerror(err));
        exit(1);
    }

    if ((err = snd_pcm_hw_params_set_rate_near(playback_handle, hw_params,
                    &rate, &dir)) < 0) {
        fprintf(stderr, "cannot set sample rate (%s)\n",
                snd_strerror(err));
        exit(1);
    }

    if ((err = snd_pcm_hw_params_set_channels_first (playback_handle, hw_params, &channels)) < 0) {
        fprintf(stderr, "cannot set channels to first (%s)\n",
                snd_strerror(err));
        exit(1);
    }

    if ((err = snd_pcm_hw_params_set_buffer_time_last (playback_handle, hw_params, &buffer_time, &dir)) < 0) {
        fprintf(stderr, "cannot set buffer time to last (%s)\n",
                snd_strerror(err));
        exit(1);
    }

    if ((err = snd_pcm_hw_params(playback_handle, hw_params)) < 0) {
        fprintf(stderr, "cannot set parameters (%s)\n",  snd_strerror(err));
        exit(1);
    }

    snd_pcm_uframes_t bufsize;
    snd_pcm_hw_params_get_buffer_size(hw_params, &bufsize);
    printf("bufsize %lu\n", bufsize);

    snd_pcm_hw_params_free (hw_params);

    if ((err = snd_pcm_prepare(playback_handle)) < 0) {
        fprintf (stderr, "cannot prepare audio interface for use (%s)\n",
                snd_strerror(err));
        exit(1);
    }

    buf = calloc(channels * BUFSIZE, 2);
    for (i = 0; i < BUFSIZE; i++) {
        int16_t val = (int16_t)(sin(2.0*PI*i/(rate/frequency)) * 16384.0);
        buf[channels*i] = val;
    }

    printf("queue data %d\n", iters);
    snd_pcm_uframes_t written = 0;
    for (i = 0; i < iters; i++) {
        written += snd_pcm_writei(playback_handle, buf, BUFSIZE);
        if(written > rate) {
            snd_pcm_drop(playback_handle);
            snd_pcm_prepare(playback_handle);
            written -= rate;
            printf("drop; playback should stop _now_\n");
        }
    }
    printf("done queuing\n");
    printf("dropping one last time\n");
    snd_pcm_drop(playback_handle);

    printf("playback should have long stopped by now\n");
    sleep(10);

    snd_pcm_close(playback_handle);
    exit(0);
}