Merge branch 'refs/heads/t/tarball-build-fix'

[paraslash.git] / alsa_write.c

diff --git a/alsa_write.c b/alsa_write.c
index 11e4504d79e78c8e613fc33baec80ef168e72f20..43b26868bef5abdf3d9268cc93f7b1ca8524693f 100644 (file)
--- a/alsa_write.c
+++ b/alsa_write.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2005-2013 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
  *
  * 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;
@@ -77,9 +79,9 @@ static int alsa_init(struct private_alsa_write_data *pad,
        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";
@@ -112,18 +114,21 @@ 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, 0);
+       if (ret < 0)
+               goto fail;
+
        msg = "unable to install hw params";
        ret = snd_pcm_hw_params(pad->handle, hwparams);
        if (ret < 0)
@@ -194,10 +199,10 @@ fail:
        return -E_ALSA;
 }
 
-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 +218,8 @@ 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 +248,9 @@ 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 +258,7 @@ 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:
@@ -301,21 +307,13 @@ 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) {