pulseaudio/src/modules/alsa-util.c

/* $Id$ */

/***
  This file is part of PulseAudio.

  Copyright 2004-2006 Lennart Poettering
  Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB

  PulseAudio is free software; you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as published
  by the Free Software Foundation; either version 2 of the License,
  or (at your option) any later version.

  PulseAudio is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with PulseAudio; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  USA.
***/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <sys/types.h>
#include <asoundlib.h>

#include <pulse/sample.h>
#include <pulse/xmalloc.h>

#include <pulsecore/log.h>

#include "alsa-util.h"

static int set_format(snd_pcm_t *pcm_handle, snd_pcm_hw_params_t *hwparams, pa_sample_format_t *f) {

    static const snd_pcm_format_t format_trans[] = {
        [PA_SAMPLE_U8] = SND_PCM_FORMAT_U8,
        [PA_SAMPLE_ALAW] = SND_PCM_FORMAT_A_LAW,
        [PA_SAMPLE_ULAW] = SND_PCM_FORMAT_MU_LAW,
        [PA_SAMPLE_S16LE] = SND_PCM_FORMAT_S16_LE,
        [PA_SAMPLE_S16BE] = SND_PCM_FORMAT_S16_BE,
        [PA_SAMPLE_FLOAT32LE] = SND_PCM_FORMAT_FLOAT_LE,
        [PA_SAMPLE_FLOAT32BE] = SND_PCM_FORMAT_FLOAT_BE,
    };

    static const pa_sample_format_t try_order[] = {
        PA_SAMPLE_S16NE,
        PA_SAMPLE_S16RE,
        PA_SAMPLE_FLOAT32NE,
        PA_SAMPLE_FLOAT32RE,
        PA_SAMPLE_ULAW,
        PA_SAMPLE_ALAW,
        PA_SAMPLE_U8,
        PA_SAMPLE_INVALID
    };

    int i, ret;

    assert(pcm_handle);
    assert(f);

    if ((ret = snd_pcm_hw_params_set_format(pcm_handle, hwparams, format_trans[*f])) >= 0)
        return ret;

    if (*f == PA_SAMPLE_FLOAT32BE)
        *f = PA_SAMPLE_FLOAT32LE;
    else if (*f == PA_SAMPLE_FLOAT32LE)
        *f = PA_SAMPLE_FLOAT32BE;
    else if (*f == PA_SAMPLE_S16BE)
        *f = PA_SAMPLE_S16LE;
    else if (*f == PA_SAMPLE_S16LE)
        *f = PA_SAMPLE_S16BE;
    else
        goto try_auto;

    if ((ret = snd_pcm_hw_params_set_format(pcm_handle, hwparams, format_trans[*f])) >= 0)
        return ret;

try_auto:

    for (i = 0; try_order[i] != PA_SAMPLE_INVALID; i++) {
        *f = try_order[i];

        if ((ret = snd_pcm_hw_params_set_format(pcm_handle, hwparams, format_trans[*f])) >= 0)
            return ret;
    }

    return -1;
}

/* Set the hardware parameters of the given ALSA device. Returns the
 * selected fragment settings in *period and *period_size */
int pa_alsa_set_hw_params(snd_pcm_t *pcm_handle, pa_sample_spec *ss, uint32_t *periods, snd_pcm_uframes_t *period_size, int *use_mmap) {
    int ret = -1;
    snd_pcm_uframes_t buffer_size;
    unsigned int r = ss->rate;
    unsigned int c = ss->channels;
    pa_sample_format_t f = ss->format;
    snd_pcm_hw_params_t *hwparams;

    assert(pcm_handle);
    assert(ss);
    assert(periods);
    assert(period_size);

    buffer_size = *periods * *period_size;

    if ((ret = snd_pcm_hw_params_malloc(&hwparams)) < 0 ||
        (ret = snd_pcm_hw_params_any(pcm_handle, hwparams)) < 0 ||
        (ret = snd_pcm_hw_params_set_rate_resample(pcm_handle, hwparams, 0)) < 0)
        goto finish;

    if (use_mmap && *use_mmap) {
        if ((ret = snd_pcm_hw_params_set_access(pcm_handle, hwparams, SND_PCM_ACCESS_MMAP_INTERLEAVED)) < 0)
            if ((ret = snd_pcm_hw_params_set_access(pcm_handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0)
                goto finish;

    } else if ((ret = snd_pcm_hw_params_set_access(pcm_handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) 
        goto finish;
    else if (*use_mmap)
        *use_mmap = 0;
    
    if ((ret = set_format(pcm_handle, hwparams, &f)) < 0)
        goto finish;

    if ((ret = snd_pcm_hw_params_set_rate_near(pcm_handle, hwparams, &r, NULL)) < 0)
        goto finish;

    if ((ret = snd_pcm_hw_params_set_channels_near(pcm_handle, hwparams, &c)) < 0)
        goto finish;

    if ((*period_size > 0 && (ret = snd_pcm_hw_params_set_period_size_near(pcm_handle, hwparams, period_size, NULL)) < 0) ||
        (*periods > 0 && (ret = snd_pcm_hw_params_set_buffer_size_near(pcm_handle, hwparams, &buffer_size)) < 0))
        goto finish;

    if  ((ret = snd_pcm_hw_params(pcm_handle, hwparams)) < 0)
        goto finish;

    if (ss->rate != r) {
        pa_log_warn("device doesn't support %u Hz, changed to %u Hz.", ss->rate, r);

        /* If the sample rate deviates too much, we need to resample */
        if (r < ss->rate*.95 || r > ss->rate*1.05)
            ss->rate = r;
    }

    if (ss->channels != c) {
        pa_log_warn("device doesn't support %u channels, changed to %u.", ss->channels, c);
        ss->channels = c;
    }

    if (ss->format != f) {
        pa_log_warn("device doesn't support sample format %s, changed to %s.", pa_sample_format_to_string(ss->format), pa_sample_format_to_string(f));
        ss->format = f;
    }

    if ((ret = snd_pcm_prepare(pcm_handle)) < 0)
        goto finish;

    if ((ret = snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size)) < 0 ||
        (ret = snd_pcm_hw_params_get_period_size(hwparams, period_size, NULL)) < 0)
        goto finish;

    assert(buffer_size > 0);
    assert(*period_size > 0);
    *periods = buffer_size / *period_size;
    assert(*periods > 0);

    ret = 0;

finish:
    if (hwparams)
        snd_pcm_hw_params_free(hwparams);

    return ret;
}

int pa_alsa_prepare_mixer(snd_mixer_t *mixer, const char *dev) {
    int err;

    assert(mixer && dev);

    if ((err = snd_mixer_attach(mixer, dev)) < 0) {
        pa_log_warn("Unable to attach to mixer %s: %s", dev, snd_strerror(err));
        return -1;
    }

    if ((err = snd_mixer_selem_register(mixer, NULL, NULL)) < 0) {
        pa_log_warn("Unable to register mixer: %s", snd_strerror(err));
        return -1;
    }

    if ((err = snd_mixer_load(mixer)) < 0) {
        pa_log_warn("Unable to load mixer: %s", snd_strerror(err));
        return -1;
    }

    return 0;
}

snd_mixer_elem_t *pa_alsa_find_elem(snd_mixer_t *mixer, const char *name, const char *fallback) {
    snd_mixer_elem_t *elem;
    snd_mixer_selem_id_t *sid = NULL;
    snd_mixer_selem_id_alloca(&sid);

    assert(mixer);
    assert(name);

    snd_mixer_selem_id_set_name(sid, name);

    if (!(elem = snd_mixer_find_selem(mixer, sid))) {
        pa_log_warn("Cannot find mixer control \"%s\".", snd_mixer_selem_id_get_name(sid));

        if (fallback) {
            snd_mixer_selem_id_set_name(sid, fallback);

            if (!(elem = snd_mixer_find_selem(mixer, sid)))
                pa_log_warn("Cannot find fallback mixer control \"%s\".", snd_mixer_selem_id_get_name(sid));
        }
    }

    if (elem)
        pa_log_info("Using mixer control \"%s\".", snd_mixer_selem_id_get_name(sid));

    return elem;
}