Convert receivers to lopsub.
[paraslash.git] / alsa_write.c
index ba844db..fd3b404 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2005-2013 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -15,7 +15,6 @@
 #include <regex.h>
 #include <sys/types.h>
 #include <alsa/asoundlib.h>
-#include <sys/time.h>
 
 #include "para.h"
 #include "fd.h"
@@ -35,17 +34,24 @@ struct private_alsa_write_data {
        snd_pcm_t *handle;
        /** Determined and set by alsa_init(). */
        int bytes_per_frame;
-       /**
-        * The sample rate given by command line option or the decoder
-        * of the writer node group.
+       /*
+        * If the sample rate is not given at the command line and no wav
+        * header was detected, the btr exec mechanism is employed to query the
+        * ancestor buffer tree nodes for this information. In a typical setup
+        * the decoder passes the sample rate back to the alsa writer.
+        *
+        *  \sa \ref btr_exec_up().
         */
        unsigned sample_rate;
-       snd_pcm_format_t sample_format;
-       /**
-        * The number of channels, given by command line option or the
-        * decoder of the writer node group.
+       /*
+        * The sample format (8/16 bit, signed/unsigned, little/big endian) is
+        * determined in the same way as the \a sample_rate.
         */
+       snd_pcm_format_t sample_format;
+       /* The number of channels, again determined like \a sample_rate. */
        unsigned channels;
+       /* time until buffer underrun occurs, in milliseconds */
+       unsigned buffer_time;
        struct timeval drain_barrier;
        /* File descriptor for select(). */
        int poll_fd;
@@ -68,14 +74,14 @@ static snd_pcm_format_t get_alsa_pcm_format(enum sample_format sf)
 static int alsa_init(struct private_alsa_write_data *pad,
                struct alsa_write_args_info *conf)
 {
-       snd_pcm_hw_params_t *hwparams;
-       snd_pcm_sw_params_t *swparams;
+       snd_pcm_hw_params_t *hwparams = NULL;
+       snd_pcm_sw_params_t *swparams = NULL;
        snd_pcm_uframes_t start_threshold, stop_threshold;
        snd_pcm_uframes_t buffer_size, period_size;
        snd_output_t *output_log;
-       unsigned buffer_time;
        int ret;
        const char *msg;
+       unsigned period_time;
 
        PARA_INFO_LOG("opening %s\n", conf->device_arg);
        msg = "unable to open pcm";
@@ -83,7 +89,8 @@ static int alsa_init(struct private_alsa_write_data *pad,
                SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
        if (ret < 0)
                goto fail;
-       snd_pcm_hw_params_alloca(&hwparams);
+       ret = snd_pcm_hw_params_malloc(&hwparams);
+       assert(ret >= 0);
        msg = "Broken alsa configuration";
        ret = snd_pcm_hw_params_any(pad->handle, hwparams);
        if (ret < 0)
@@ -108,18 +115,21 @@ static int alsa_init(struct private_alsa_write_data *pad,
                &pad->sample_rate, NULL);
        if (ret < 0)
                goto fail;
-       msg = "unable to get buffer time";
-       ret = snd_pcm_hw_params_get_buffer_time_max(hwparams, &buffer_time,
-               NULL);
-       if (ret < 0 || buffer_time == 0)
-               goto fail;
-       /* buffer at most 500 milliseconds */
-       buffer_time = PARA_MIN(buffer_time, 500U * 1000U);
+       /* alsa wants microseconds */
+       pad->buffer_time = conf->buffer_time_arg * 1000;
        msg = "could not set buffer time";
        ret = snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
-               &buffer_time, NULL);
+               &pad->buffer_time, NULL);
+       if (ret < 0)
+               goto fail;
+       pad->buffer_time /= 1000; /* we prefer milliseconds */
+       period_time = pad->buffer_time * 250; /* buffer time / 4 */
+       msg = "could not set period time";
+       ret = snd_pcm_hw_params_set_period_time_near(pad->handle, hwparams,
+               &period_time, NULL);
        if (ret < 0)
                goto fail;
+
        msg = "unable to install hw params";
        ret = snd_pcm_hw_params(pad->handle, hwparams);
        if (ret < 0)
@@ -131,7 +141,8 @@ static int alsa_init(struct private_alsa_write_data *pad,
                goto fail;
 
        /* software parameter setup */
-       snd_pcm_sw_params_alloca(&swparams);
+       ret = snd_pcm_sw_params_malloc(&swparams);
+       assert(ret >= 0);
        snd_pcm_sw_params_current(pad->handle, swparams);
        snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
        if (buffer_size < 1)
@@ -165,33 +176,40 @@ static int alsa_init(struct private_alsa_write_data *pad,
                goto fail;
        ret = snd_output_buffer_open(&output_log);
        if (ret == 0) {
-               char *buf;
-               PARA_INFO_LOG("dumping alsa configuration\n");
+               char *buf, *p;
+               size_t sz;
+               PARA_DEBUG_LOG("dumping alsa configuration\n");
                snd_pcm_dump(pad->handle, output_log);
-               snd_output_buffer_string(output_log, &buf);
-               for (;;) {
-                       char *p = strchr(buf, '\n');
-                       if (!p) /* omit last output line, it's empty */
+               snd_pcm_hw_params_dump(hwparams, output_log);
+               sz = snd_output_buffer_string(output_log, &buf);
+               for (p = buf; p < buf + sz;) {
+                       char *q = memchr(p, '\n', buf + sz - p);
+                       if (!q)
                                break;
-                       *p = '\0';
-                       PARA_INFO_LOG("%s\n", buf);
-                       buf = p + 1;
+                       *q = '\0';
+                       PARA_DEBUG_LOG("%s\n", p);
+                       p = q + 1;
                }
                snd_output_close(output_log);
        }
-       return 1;
+       ret = 1;
+       goto out;
 fail:
        if (ret < 0)
                PARA_ERROR_LOG("%s: %s\n", msg, snd_strerror(-ret));
        else
                PARA_ERROR_LOG("%s\n", msg);
-       return -E_ALSA;
+       ret = -E_ALSA;
+out:
+       snd_pcm_hw_params_free(hwparams);
+       snd_pcm_sw_params_free(swparams);
+       return ret;
 }
 
-static void alsa_write_pre_select(struct sched *s, struct task *t)
+static void alsa_write_pre_select(struct sched *s, void *context)
 {
        struct pollfd pfd;
-       struct writer_node *wn = container_of(t, struct writer_node, task);
+       struct writer_node *wn = context;
        struct private_alsa_write_data *pad = wn->private_data;
        int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
 
@@ -207,11 +225,12 @@ static void alsa_write_pre_select(struct sched *s, struct task *t)
                sched_request_barrier_or_min_delay(&pad->drain_barrier, s);
                return;
        }
+       /* wait at most 50% of the buffer time */
+       sched_request_timeout_ms(pad->buffer_time / 2, s);
        ret = snd_pcm_poll_descriptors(pad->handle, &pfd, 1);
        if (ret < 0) {
                PARA_ERROR_LOG("could not get alsa poll fd: %s\n",
                        snd_strerror(-ret));
-               t->error = -E_ALSA;
                return;
        }
        pad->poll_fd = pfd.fd;
@@ -236,10 +255,9 @@ static void alsa_close(struct writer_node *wn)
        free(pad);
 }
 
-static void alsa_write_post_select(__a_unused struct sched *s,
-               struct task *t)
+static int alsa_write_post_select(__a_unused struct sched *s, void *context)
 {
-       struct writer_node *wn = container_of(t, struct writer_node, task);
+       struct writer_node *wn = context;
        struct private_alsa_write_data *pad = wn->private_data;
        struct btr_node *btrn = wn->btrn;
        char *data;
@@ -247,13 +265,13 @@ static void alsa_write_post_select(__a_unused struct sched *s,
        snd_pcm_sframes_t frames;
        int ret;
 
-       ret = task_get_notification(t);
+       ret = task_get_notification(wn->task);
        if (ret < 0)
                goto err;
 again:
        ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
        if (ret == 0)
-               return;
+               return 0;
        btr_merge(btrn, wn->min_iqs);
        bytes = btr_next_buffer(btrn, &data);
        if (ret < 0 || bytes < wn->min_iqs) { /* eof */
@@ -266,17 +284,17 @@ again:
                        PARA_DEBUG_LOG("waiting for device to drain\n");
                        tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
                                &pad->drain_barrier);
-                       return;
+                       return 0;
                }
                if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
                        goto err;
-               return;
+               return 0;
        }
        if (!pad) {
                int32_t val;
 
                if (bytes == 0) /* no data available */
-                       return;
+                       return 0;
                pad = para_calloc(sizeof(*pad));
                get_btr_sample_rate(btrn, &val);
                pad->sample_rate = val;
@@ -285,7 +303,7 @@ again:
                get_btr_sample_format(btrn, &val);
                pad->sample_format = get_alsa_pcm_format(val);
 
-               PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels,
+               PARA_INFO_LOG("%u channel(s), %uHz\n", pad->channels,
                        pad->sample_rate);
                ret = alsa_init(pad, wn->conf);
                if (ret < 0) {
@@ -296,22 +314,14 @@ again:
                wn->min_iqs = pad->bytes_per_frame;
                goto again;
        }
-       if (pad->poll_fd < 0 || !FD_ISSET(pad->poll_fd, &s->rfds))
-               return;
        frames = bytes / pad->bytes_per_frame;
        frames = snd_pcm_writei(pad->handle, data, frames);
        if (frames == 0 || frames == -EAGAIN) {
-               /*
-                * The alsa poll fd was ready for IO but we failed to write to
-                * the alsa handle. This means another event is pending. We
-                * don't care about that but we have to dispatch the event in
-                * order to avoid a busy loop. So we simply read from the poll
-                * fd.
-                */
                char buf[100];
-               if (read(pad->poll_fd, buf, 100))
-                       do_nothing;
-               return;
+               if (pad->poll_fd >= 0 && FD_ISSET(pad->poll_fd, &s->rfds))
+                       if (read(pad->poll_fd, buf, 100))
+                               do_nothing;
+               return 0;
        }
        if (frames > 0) {
                btr_consume(btrn, frames * pad->bytes_per_frame);
@@ -320,14 +330,14 @@ again:
        if (frames == -EPIPE) {
                PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
                snd_pcm_prepare(pad->handle);
-               return;
+               return 0;
        }
        PARA_ERROR_LOG("alsa write error: %s\n", snd_strerror(-frames));
        ret = -E_ALSA;
 err:
        assert(ret < 0);
        btr_remove_node(&wn->btrn);
-       t->error = ret;
+       return ret;
 }
 
 __malloc static void *alsa_parse_config_or_die(int argc, char **argv)
@@ -361,9 +371,6 @@ void alsa_write_init(struct writer *w)
        w->post_select = alsa_write_post_select;
        w->parse_config_or_die = alsa_parse_config_or_die;
        w->free_config = alsa_free_config;
-       w->help = (struct ggo_help) {
-               .short_help = alsa_write_args_info_help,
-               .detailed_help = alsa_write_args_info_detailed_help
-       };
+       w->help = (struct ggo_help)DEFINE_GGO_HELP(alsa_write);
        alsa_write_cmdline_parser_free(&dummy);
 }