X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=alsa_write.c;h=ad59a829e4d0967bad079b9df6caa0e976b8f77b;hp=8cf5cfd25bf3909e0f4d338d2397ca0e017c29ab;hb=027f2c1237051d2d569d6be7f381c886f659bac3;hpb=290d89f17769d1ad8fe9abb5e432939268f74f1a diff --git a/alsa_write.c b/alsa_write.c index 8cf5cfd2..ad59a829 100644 --- a/alsa_write.c +++ b/alsa_write.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2005-2011 Andre Noll + * Copyright (C) 2005-2014 Andre Noll * * Licensed under the GPL v2. For licencing details see COPYING. */ @@ -14,10 +14,7 @@ #include #include -#include #include -#include -#include #include "para.h" #include "fd.h" @@ -37,10 +34,6 @@ struct private_alsa_write_data { snd_pcm_t *handle; /** Determined and set by alsa_init(). */ int bytes_per_frame; - /** The approximate maximum buffer duration in us. */ - unsigned buffer_time; - /* Number of frames that fit into the buffer. */ - snd_pcm_uframes_t buffer_frames; /** * The sample rate given by command line option or the decoder * of the writer node group. @@ -53,6 +46,8 @@ struct private_alsa_write_data { */ unsigned channels; struct timeval drain_barrier; + /* File descriptor for select(). */ + int poll_fd; }; static snd_pcm_format_t get_alsa_pcm_format(enum sample_format sf) @@ -75,105 +70,152 @@ static int alsa_init(struct private_alsa_write_data *pad, snd_pcm_hw_params_t *hwparams; snd_pcm_sw_params_t *swparams; snd_pcm_uframes_t start_threshold, stop_threshold; - snd_pcm_uframes_t period_size; - int err; + snd_pcm_uframes_t buffer_size, period_size; + snd_output_t *output_log; + unsigned buffer_time; + int ret; + const char *msg; PARA_INFO_LOG("opening %s\n", conf->device_arg); - err = snd_pcm_open(&pad->handle, conf->device_arg, + msg = "unable to open pcm"; + ret = snd_pcm_open(&pad->handle, conf->device_arg, SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK); - if (err < 0) - return -E_PCM_OPEN; - + if (ret < 0) + goto fail; snd_pcm_hw_params_alloca(&hwparams); - snd_pcm_sw_params_alloca(&swparams); - if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0) - return -E_BROKEN_CONF; - if (snd_pcm_hw_params_set_access(pad->handle, hwparams, - SND_PCM_ACCESS_RW_INTERLEAVED) < 0) - return -E_ACCESS_TYPE; - if (snd_pcm_hw_params_set_format(pad->handle, hwparams, - pad->sample_format) < 0) - return -E_SAMPLE_FORMAT; - if (snd_pcm_hw_params_set_channels(pad->handle, hwparams, - pad->channels) < 0) - return -E_CHANNEL_COUNT; - if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams, - &pad->sample_rate, NULL) < 0) - return -E_SET_RATE; - err = snd_pcm_hw_params_get_buffer_time_max(hwparams, - &pad->buffer_time, NULL); - if (err < 0 || !pad->buffer_time) - return -E_GET_BUFFER_TIME; - PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time); - if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams, - &pad->buffer_time, NULL) < 0) - return -E_SET_BUFFER_TIME; - if (snd_pcm_hw_params(pad->handle, hwparams) < 0) - return -E_HW_PARAMS; + msg = "Broken alsa configuration"; + ret = snd_pcm_hw_params_any(pad->handle, hwparams); + if (ret < 0) + goto fail; + msg = "access type not available"; + ret = snd_pcm_hw_params_set_access(pad->handle, hwparams, + SND_PCM_ACCESS_RW_INTERLEAVED); + if (ret < 0) + goto fail; + msg = "sample format not available"; + ret = snd_pcm_hw_params_set_format(pad->handle, hwparams, + pad->sample_format); + if (ret < 0) + goto fail; + msg = "channels count not available"; + ret = snd_pcm_hw_params_set_channels(pad->handle, hwparams, + pad->channels); + if (ret < 0) + goto fail; + msg = "could not set sample rate"; + ret = snd_pcm_hw_params_set_rate_near(pad->handle, hwparams, + &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); + msg = "could not set buffer time"; + ret = snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams, + &buffer_time, NULL); + if (ret < 0) + goto fail; + msg = "unable to install hw params"; + ret = snd_pcm_hw_params(pad->handle, hwparams); + if (ret < 0) + goto fail; snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL); - snd_pcm_hw_params_get_buffer_size(hwparams, &pad->buffer_frames); - PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", pad->buffer_frames, - period_size); - if (period_size == pad->buffer_frames) - return -E_BAD_PERIOD; + snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size); + msg = "period size equals buffer size"; + if (period_size == buffer_size) + goto fail; + + /* software parameter setup */ + snd_pcm_sw_params_alloca(&swparams); snd_pcm_sw_params_current(pad->handle, swparams); snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size); - if (pad->buffer_frames < 1) + if (buffer_size < 1) start_threshold = 1; else - start_threshold = PARA_MIN(pad->buffer_frames, + start_threshold = PARA_MIN(buffer_size, (snd_pcm_uframes_t)pad->sample_rate); - if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams, - start_threshold) < 0) - return -E_START_THRESHOLD; - stop_threshold = pad->buffer_frames; - if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams, - stop_threshold) < 0) - return -E_STOP_THRESHOLD; - if (snd_pcm_sw_params(pad->handle, swparams) < 0) - PARA_WARNING_LOG("unable to install sw params\n"); - pad->bytes_per_frame = snd_pcm_format_physical_width(pad->sample_format) - * pad->channels / 8; - if (pad->bytes_per_frame <= 0) - return -E_PHYSICAL_WIDTH; - PARA_INFO_LOG("bytes per frame: %d\n", pad->bytes_per_frame); - if (snd_pcm_nonblock(pad->handle, 1)) - PARA_ERROR_LOG("failed to set nonblock mode\n"); + msg = "could not set start threshold"; + ret = snd_pcm_sw_params_set_start_threshold(pad->handle, swparams, + start_threshold); + if (ret < 0) + goto fail; + stop_threshold = buffer_size; + msg = "could not set stop threshold"; + ret = snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams, + stop_threshold); + if (ret < 0) + goto fail; + msg = "unable to install sw params"; + ret = snd_pcm_sw_params(pad->handle, swparams); + if (ret < 0) + goto fail; + msg = "unable to determine bytes per frame"; + ret = snd_pcm_format_physical_width(pad->sample_format); + if (ret <= 0) + goto fail; + pad->bytes_per_frame = ret * pad->channels / 8; + msg = "failed to set alsa handle to nonblock mode"; + ret = snd_pcm_nonblock(pad->handle, 1); + if (ret < 0) + goto fail; + ret = snd_output_buffer_open(&output_log); + if (ret == 0) { + char *buf, *p; + size_t sz; + PARA_INFO_LOG("dumping alsa configuration\n"); + snd_pcm_dump(pad->handle, 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; + *q = '\0'; + PARA_INFO_LOG("%s\n", p); + p = q + 1; + } + snd_output_close(output_log); + } return 1; +fail: + if (ret < 0) + PARA_ERROR_LOG("%s: %s\n", msg, snd_strerror(-ret)); + else + PARA_ERROR_LOG("%s\n", msg); + return -E_ALSA; } static void alsa_write_pre_select(struct sched *s, struct task *t) { + struct pollfd pfd; struct writer_node *wn = container_of(t, struct writer_node, task); struct private_alsa_write_data *pad = wn->private_data; - struct timeval tv; - snd_pcm_sframes_t avail, underrun; int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF); + if (pad) + pad->poll_fd = -1; if (ret == 0) return; - if (ret < 0 || !pad) - return sched_min_delay(s); - /* - * Data is available to be written to the alsa handle. Compute number - * of milliseconds until next buffer underrun would occur. - * - * snd_pcm_avail_update() updates the current available count of - * samples for writing. It is a light method to obtain current stream - * position, because it does not require the user <-> kernel context - * switch, but the value is less accurate, because ring buffer pointers - * are updated in kernel drivers only when an interrupt occurs. - */ - avail = snd_pcm_avail_update(pad->handle); - if (avail < 0) - avail = 0; - underrun = (pad->buffer_frames - avail) * pad->buffer_time - / pad->buffer_frames / 1000; - if (underrun < 50) - underrun = 50; - underrun -= 50; - ms2tv(underrun, &tv); - sched_request_timeout(&tv, s); + if (!pad) { + sched_min_delay(s); + return; + } + if (ret < 0) { + sched_request_barrier_or_min_delay(&pad->drain_barrier, s); + return; + } + 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; + para_fd_set(pfd.fd, &s->rfds, &s->max_fileno); } static void alsa_close(struct writer_node *wn) @@ -194,7 +236,7 @@ static void alsa_close(struct writer_node *wn) free(pad); } -static void alsa_write_post_select(__a_unused struct sched *s, +static int alsa_write_post_select(__a_unused struct sched *s, struct task *t) { struct writer_node *wn = container_of(t, struct writer_node, task); @@ -205,11 +247,13 @@ static void alsa_write_post_select(__a_unused struct sched *s, snd_pcm_sframes_t frames; int ret; + ret = task_get_notification(t); + if (ret < 0) + goto err; again: - t->error = 0; 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 */ @@ -222,17 +266,17 @@ 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; @@ -252,40 +296,52 @@ again: wn->min_iqs = pad->bytes_per_frame; goto again; } + if (pad->poll_fd < 0 || !FD_ISSET(pad->poll_fd, &s->rfds)) + return 0; frames = bytes / pad->bytes_per_frame; frames = snd_pcm_writei(pad->handle, data, frames); - if (frames >= 0) { + 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 0; + } + if (frames > 0) { btr_consume(btrn, frames * pad->bytes_per_frame); goto again; } if (frames == -EPIPE) { PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes); snd_pcm_prepare(pad->handle); - return; + return 0; } - if (frames == -EAGAIN) - return; - PARA_WARNING_LOG("%s\n", snd_strerror(-frames)); - ret = -E_ALSA_WRITE; + PARA_ERROR_LOG("alsa write error: %s\n", snd_strerror(-frames)); + ret = -E_ALSA; err: assert(ret < 0); - btr_remove_node(btrn); - t->error = ret; + btr_remove_node(&wn->btrn); + return ret; } -__malloc static void *alsa_parse_config_or_die(const char *options) +__malloc static void *alsa_parse_config_or_die(int argc, char **argv) { struct alsa_write_args_info *conf = para_calloc(sizeof(*conf)); - PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t")); /* exits on errors */ - alsa_cmdline_parser_string(options, conf, "alsa_write"); + alsa_write_cmdline_parser(argc, argv, conf); return conf; } static void alsa_free_config(void *conf) { - alsa_cmdline_parser_free(conf); + alsa_write_cmdline_parser_free(conf); } /** @@ -299,16 +355,12 @@ void alsa_write_init(struct writer *w) { struct alsa_write_args_info dummy; - alsa_cmdline_parser_init(&dummy); + alsa_write_cmdline_parser_init(&dummy); w->close = alsa_close; w->pre_select = alsa_write_pre_select; w->post_select = alsa_write_post_select; w->parse_config_or_die = alsa_parse_config_or_die; - w->shutdown = NULL; /* nothing to do */ 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 - }; - alsa_cmdline_parser_free(&dummy); + w->help = (struct ggo_help)DEFINE_GGO_HELP(alsa_write); + alsa_write_cmdline_parser_free(&dummy); }