Merge branch 't/alsa_poll_fd'

[paraslash.git] / alsa_write.c

diff --git a/alsa_write.c b/alsa_write.c
index 6850221a83d861e04cfcd8254d3114f837013a2e..047e88f2200a45f2518c7f1508874108e26a6bce 100644 (file)
--- a/alsa_write.c
+++ b/alsa_write.c
@@ -52,6 +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)
@@ -143,36 +145,31 @@ static int alsa_init(struct private_alsa_write_data *pad,
 
 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;
-       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 (!pad)
-               return sched_min_delay(s);
-       if (ret < 0)
-               return sched_request_barrier_or_min_delay(&pad->drain_barrier, 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;
-       sched_request_timeout_ms(underrun, 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)
@@ -251,6 +248,8 @@ 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);
        if (frames == 0 || frames == -EAGAIN)
@@ -276,7 +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;