X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=alsa_write.c;h=fd3b404c0359c1a571255b1ac7265b0ee0faef41;hp=11e4504d79e78c8e613fc33baec80ef168e72f20;hb=bc78a94412b17dfd445d6bb88f752041df3cf7ba;hpb=4eb15d1cf4dbd3b2962cdd3930e2d9559acb248e diff --git a/alsa_write.c b/alsa_write.c index 11e4504d..fd3b404c 100644 --- a/alsa_write.c +++ b/alsa_write.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2005-2013 Andre Noll + * Copyright (C) 2005 Andre Noll * * Licensed under the GPL v2. For licencing details see COPYING. */ @@ -50,6 +50,8 @@ struct private_alsa_write_data { 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; @@ -72,14 +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"; @@ -87,7 +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) @@ -112,18 +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) @@ -135,7 +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) @@ -185,19 +192,24 @@ static int alsa_init(struct private_alsa_write_data *pad, } 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); @@ -213,6 +225,8 @@ 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", @@ -241,10 +255,9 @@ static void alsa_close(struct writer_node *wn) free(pad); } -static int 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; @@ -252,7 +265,7 @@ static int 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: @@ -290,7 +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) { @@ -301,21 +314,13 @@ 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 || 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; + 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) {