X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=alsa_write.c;h=a4863a59a5bc3a426a08e6a69d333bded736d780;hp=aa772daaae48bbd135d222b0eca3d70543d3060c;hb=869f0e06ec4e15abc9230c1b2d7615da5250802e;hpb=bb991c66000ea867d0fcbd692ffdc5473eb785fb;ds=sidebyside

diff --git a/alsa_write.c b/alsa_write.c
index aa772daa..a4863a59 100644
--- a/alsa_write.c
+++ b/alsa_write.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2005-2010 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005-2012 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -14,10 +14,8 @@
 
 #include <regex.h>
 #include <sys/types.h>
-#include <dirent.h>
 #include <alsa/asoundlib.h>
 #include <sys/time.h>
-#include <stdbool.h>
 
 #include "para.h"
 #include "fd.h"
@@ -35,12 +33,8 @@
 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;
-	/* 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 +47,8 @@ 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)
@@ -75,115 +71,149 @@ 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 *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;
+	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");
-	return 1;
-}
-
-/* Open an instance of the alsa writer. */
-static int alsa_open(struct writer_node *wn)
-{
-	wn->private_data = para_calloc(sizeof(struct private_alsa_write_data));
+	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(&log);
+	if (ret == 0) {
+		char *buf;
+		PARA_INFO_LOG("dumping alsa configuration\n");
+		snd_pcm_dump(pad->handle, log);
+		snd_output_buffer_string(log, &buf);
+		for (;;) {
+			char *p = strchr(buf, '\n');
+			if (!p) /* omit last output line, it's empty */
+				break;
+			*p = '\0';
+			PARA_INFO_LOG("%s\n", buf);
+			buf = p + 1;
+		}
+		snd_output_close(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;
+	int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
 
-	if (!pad->handle)
+	if (pad)
+		pad->poll_fd = -1;
+	if (ret == 0)
 		return;
-	ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
-	if (ret < 0)
-		sched_request_timeout_ms(20, s);
-	if (ret <= 0)
+	if (!pad) {
+		sched_min_delay(s);
 		return;
-	/*
-	 * 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 (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)
@@ -191,16 +221,16 @@ 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);
 }
 
@@ -222,10 +252,10 @@ 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) {
@@ -238,11 +268,12 @@ 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);
@@ -253,14 +284,32 @@ 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) {
+		/*
+		 * 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 (frames > 0) {
 		btr_consume(btrn, frames * pad->bytes_per_frame);
 		goto again;
 	}
@@ -269,10 +318,8 @@ again:
 		snd_pcm_prepare(pad->handle);
 		return;
 	}
-	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);
@@ -283,7 +330,6 @@ __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;
@@ -306,7 +352,6 @@ 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;