X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=alsa_write.c;h=047e88f2200a45f2518c7f1508874108e26a6bce;hp=3428def83076b9f8b89fc4c1e41bd0c921e54fbb;hb=b307a25ed895caa33684302b502e9e0e70dc78b7;hpb=2ef39ae4d1e6b0d95991d2b980621fb152211444 diff --git a/alsa_write.c b/alsa_write.c index 3428def8..047e88f2 100644 --- a/alsa_write.c +++ b/alsa_write.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2005-2010 Andre Noll + * Copyright (C) 2005-2011 Andre Noll * * Licensed under the GPL v2. For licencing details see COPYING. */ @@ -14,7 +14,6 @@ #include #include -#include #include #include #include @@ -35,7 +34,7 @@ struct private_alsa_write_data { /** The alsa handle */ snd_pcm_t *handle; - /** Determined and set by alsa_open(). */ + /** Determined and set by alsa_init(). */ int bytes_per_frame; /** The approximate maximum buffer duration in us. */ unsigned buffer_time; @@ -53,6 +52,8 @@ 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) @@ -142,44 +143,33 @@ static int alsa_init(struct private_alsa_write_data *pad, return 1; } -/* Open an instance of the alsa writer. */ -static void alsa_open(struct writer_node *wn) -{ - wn->private_data = para_calloc(sizeof(struct private_alsa_write_data)); -} - 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->handle) - 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("%s\n", snd_strerror(-ret)); + t->error = -E_ALSA_POLL_FDS; + return; + } + pad->poll_fd = pfd.fd; + para_fd_set(pfd.fd, &s->rfds, &s->max_fileno); } static void alsa_close(struct writer_node *wn) @@ -187,16 +177,16 @@ static void alsa_close(struct writer_node *wn) struct private_alsa_write_data *pad = wn->private_data; PARA_INFO_LOG("closing writer node %p\n", wn); - if (pad->handle) { - /* - * It's OK to have a blocking operation here because we already - * made sure that the PCM output buffer is (nearly) empty. - */ - snd_pcm_nonblock(pad->handle, 0); - snd_pcm_drain(pad->handle); - snd_pcm_close(pad->handle); - snd_config_update_free_global(); - } + if (!pad) + return; + /* + * It's OK to have a blocking operation here because we already made + * sure that the PCM output buffer is (nearly) empty. + */ + snd_pcm_nonblock(pad->handle, 0); + snd_pcm_drain(pad->handle); + snd_pcm_close(pad->handle); + snd_config_update_free_global(); free(pad); } @@ -218,10 +208,10 @@ again: return; btr_merge(btrn, wn->min_iqs); bytes = btr_next_buffer(btrn, &data); - if (ret < 0 || bytes < pad->bytes_per_frame) { /* eof */ + if (ret < 0 || bytes < wn->min_iqs) { /* eof */ assert(btr_no_parent(btrn)); - ret = -E_ALSA_EOF; - if (!pad->handle) + ret = -E_WRITE_COMMON_EOF; + if (!pad) goto err; /* wait until pending frames are played */ if (pad->drain_barrier.tv_sec == 0) { @@ -234,11 +224,12 @@ again: goto err; return; } - if (!pad->handle) { + if (!pad) { int32_t val; if (bytes == 0) /* no data available */ return; + pad = para_calloc(sizeof(*pad)); get_btr_sample_rate(btrn, &val); pad->sample_rate = val; get_btr_channels(btrn, &val); @@ -249,14 +240,21 @@ again: PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->sample_rate); ret = alsa_init(pad, wn->conf); - if (ret < 0) + if (ret < 0) { + free(pad); goto err; + } + wn->private_data = pad; 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) { + if (frames == 0 || frames == -EAGAIN) + return; + if (frames > 0) { btr_consume(btrn, frames * pad->bytes_per_frame); goto again; } @@ -265,8 +263,6 @@ again: snd_pcm_prepare(pad->handle); return; } - if (frames == -EAGAIN) - return; PARA_WARNING_LOG("%s\n", snd_strerror(-frames)); ret = -E_ALSA_WRITE; err: @@ -279,7 +275,6 @@ __malloc static void *alsa_parse_config_or_die(const char *options) { 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"); return conf; @@ -302,7 +297,6 @@ void alsa_write_init(struct writer *w) struct alsa_write_args_info dummy; alsa_cmdline_parser_init(&dummy); - w->open = alsa_open; w->close = alsa_close; w->pre_select = alsa_write_pre_select; w->post_select = alsa_write_post_select;