aft.c: Silence scan-build warning.
[paraslash.git] / alsa_write.c
index 8cf5cfd..a4863a5 100644 (file)
@@ -1,5 +1,5 @@
 /*
 /*
- * Copyright (C) 2005-2011 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005-2012 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
 
 #include <regex.h>
 #include <sys/types.h>
 
 #include <regex.h>
 #include <sys/types.h>
-#include <dirent.h>
 #include <alsa/asoundlib.h>
 #include <sys/time.h>
 #include <alsa/asoundlib.h>
 #include <sys/time.h>
-#include <stdbool.h>
 
 #include "para.h"
 #include "fd.h"
 
 #include "para.h"
 #include "fd.h"
@@ -37,10 +35,6 @@ struct private_alsa_write_data {
        snd_pcm_t *handle;
        /** Determined and set by alsa_init(). */
        int bytes_per_frame;
        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.
        /**
         * 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;
         */
        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)
 };
 
 static snd_pcm_format_t get_alsa_pcm_format(enum sample_format sf)
@@ -75,105 +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_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);
 
        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);
                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_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_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);
        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 = 1;
        else
-               start_threshold = PARA_MIN(pad->buffer_frames,
+               start_threshold = PARA_MIN(buffer_size,
                        (snd_pcm_uframes_t)pad->sample_rate);
                        (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(&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;
        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)
 {
 }
 
 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 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);
 
        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)
                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)
 }
 
 static void alsa_close(struct writer_node *wn)
@@ -252,9 +292,24 @@ again:
                wn->min_iqs = pad->bytes_per_frame;
                goto 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);
        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;
        }
                btr_consume(btrn, frames * pad->bytes_per_frame);
                goto again;
        }
@@ -263,10 +318,8 @@ again:
                snd_pcm_prepare(pad->handle);
                return;
        }
                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);
 err:
        assert(ret < 0);
        btr_remove_node(btrn);
@@ -277,7 +330,6 @@ __malloc static void *alsa_parse_config_or_die(const char *options)
 {
        struct alsa_write_args_info *conf = para_calloc(sizeof(*conf));
 
 {
        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;
        /* exits on errors */
        alsa_cmdline_parser_string(options, conf, "alsa_write");
        return conf;