alsa: Probe sink/source sample rates

This probes sink and source sample rates and uses this information to
validate rate changes and check incoming passthrough formats.

src/modules/alsa/alsa-sink.c

@@ -109,6 +109,8 @@ struct userdata {
 
     pa_cvolume hardware_volume;
 
+    unsigned int *rates;
+
     size_t
         frame_size,
         fragment_size,
@@ -1509,8 +1511,8 @@ static pa_idxset* sink_get_formats(pa_sink *s) {
 
 static pa_bool_t sink_set_formats(pa_sink *s, pa_idxset *formats) {
     struct userdata *u = s->userdata;
-    pa_format_info *f;
+    pa_format_info *f, *g;
-    uint32_t idx;
+    uint32_t idx, n;
 
     pa_assert(u);
 
@@ -1528,16 +1530,26 @@ static pa_bool_t sink_set_formats(pa_sink *s, pa_idxset *formats) {
      * This is fine for now since we don't support that via the passthrough
      * framework, but this must be changed if we do. */
 
+    /* Count how many sample rates we support */
+    for (idx = 0, n = 0; u->rates[idx]; idx++)
+        n++;
+
     /* First insert non-PCM formats since we prefer those. */
     PA_IDXSET_FOREACH(f, formats, idx) {
-        if (!pa_format_info_is_pcm(f))
+        if (!pa_format_info_is_pcm(f)) {
-            pa_idxset_put(u->formats, pa_format_info_copy(f), NULL);
+            g = pa_format_info_copy(f);
+            pa_format_info_set_prop_int_array(g, PA_PROP_FORMAT_RATE, (int *) u->rates, n);
+            pa_idxset_put(u->formats, g, NULL);
+        }
     }
 
     /* Now add any PCM formats */
     PA_IDXSET_FOREACH(f, formats, idx) {
-        if (pa_format_info_is_pcm(f))
+        if (pa_format_info_is_pcm(f)) {
+            /* We don't set rates here since we'll just tack on a resampler for
+             * unsupported rates */
             pa_idxset_put(u->formats, pa_format_info_copy(f), NULL);
+        }
     }
 
     return TRUE;
@@ -1546,13 +1558,29 @@ static pa_bool_t sink_set_formats(pa_sink *s, pa_idxset *formats) {
 static pa_bool_t sink_update_rate_cb(pa_sink *s, uint32_t rate)
 {
     struct userdata *u = s->userdata;
+    int i;
+    pa_bool_t supported = FALSE;
+
     pa_assert(u);
 
+    for (i = 0; u->rates[i]; i++) {
+        if (u->rates[i] == rate) {
+            supported = TRUE;
+            break;
+        }
+    }
+
+    if (!supported) {
+        pa_log_info("Sink does not support sample rate of %d Hz", rate);
+        return FALSE;
+    }
+
     if (!PA_SINK_IS_OPENED(s->state)) {
         pa_log_info("Updating rate for device %s, new rate is %d",u->device_name, rate);
         u->sink->sample_spec.rate = rate;
         return TRUE;
     }
+
     return FALSE;
 }
 
@@ -2121,6 +2149,12 @@ pa_sink *pa_alsa_sink_new(pa_module *m, pa_modargs *ma, const char*driver, pa_ca
     if (is_iec958(u) || is_hdmi(u))
         set_formats = TRUE;
 
+    u->rates = pa_alsa_get_supported_rates(u->pcm_handle);
+    if (!u->rates) {
+        pa_log_error("Failed to find any supported sample rates.");
+        goto fail;
+    }
+
     /* ALSA might tweak the sample spec, so recalculate the frame size */
     frame_size = pa_frame_size(&ss);
 
@@ -2350,6 +2384,9 @@ static void userdata_free(struct userdata *u) {
     if (u->formats)
         pa_idxset_free(u->formats, (pa_free2_cb_t) pa_format_info_free2, NULL);
 
+    if (u->rates)
+        pa_xfree(u->rates);
+
     reserve_done(u);
     monitor_done(u);
 

src/modules/alsa/alsa-source.c

@@ -99,6 +99,8 @@ struct userdata {
 
     pa_cvolume hardware_volume;
 
+    unsigned int *rates;
+
     size_t
         frame_size,
         fragment_size,
@@ -1385,13 +1387,29 @@ static void source_update_requested_latency_cb(pa_source *s) {
 static pa_bool_t source_update_rate_cb(pa_source *s, uint32_t rate)
 {
     struct userdata *u = s->userdata;
+    int i;
+    pa_bool_t supported = FALSE;
+
     pa_assert(u);
 
+    for (i = 0; u->rates[i]; i++) {
+        if (u->rates[i] == rate) {
+            supported = TRUE;
+            break;
+        }
+    }
+
+    if (!supported) {
+        pa_log_info("Sink does not support sample rate of %d Hz", rate);
+        return FALSE;
+    }
+
     if (!PA_SOURCE_IS_OPENED(s->state)) {
         pa_log_info("Updating rate for device %s, new rate is %d", u->device_name, rate);
         u->source->sample_spec.rate = rate;
         return TRUE;
     }
+
     return FALSE;
 }
 
@@ -1862,6 +1880,12 @@ pa_source *pa_alsa_source_new(pa_module *m, pa_modargs *ma, const char*driver, p
     if (u->use_tsched)
         pa_log_info("Successfully enabled timer-based scheduling mode.");
 
+    u->rates = pa_alsa_get_supported_rates(u->pcm_handle);
+    if (!u->rates) {
+        pa_log_error("Failed to find any supported sample rates.");
+        goto fail;
+    }
+
     /* ALSA might tweak the sample spec, so recalculate the frame size */
     frame_size = pa_frame_size(&ss);
 
@@ -2062,6 +2086,9 @@ static void userdata_free(struct userdata *u) {
     if (u->smoother)
         pa_smoother_free(u->smoother);
 
+    if (u->rates)
+        pa_xfree(u->rates);
+
     reserve_done(u);
     monitor_done(u);
 

src/modules/alsa/alsa-util.c

@@ -1327,6 +1327,42 @@ char *pa_alsa_get_reserve_name(const char *device) {
     return pa_sprintf_malloc("Audio%i", i);
 }
 
+unsigned int *pa_alsa_get_supported_rates(snd_pcm_t *pcm) {
+    static unsigned int all_rates[] = { 8000, 11025, 16000, 22050, 32000, 44100, 48000, 88200, 96000, 176400, 192000, 384000 };
+    pa_bool_t supported[PA_ELEMENTSOF(all_rates)] = { FALSE, };
+    snd_pcm_hw_params_t *hwparams;
+    unsigned int i, j, n, *rates = NULL;
+    int ret;
+
+    snd_pcm_hw_params_alloca(&hwparams);
+
+    if ((ret = snd_pcm_hw_params_any(pcm, hwparams)) < 0) {
+        pa_log_debug("snd_pcm_hw_params_any() failed: %s", pa_alsa_strerror(ret));
+        return NULL;
+    }
+
+    for (i = 0, n = 0; i < PA_ELEMENTSOF(all_rates); i++) {
+        if (snd_pcm_hw_params_test_rate(pcm, hwparams, all_rates[i], 0) == 0) {
+            supported[i] = TRUE;
+            n++;
+        }
+    }
+
+    if (n == 0)
+        return NULL;
+
+    rates = pa_xnew(unsigned int, n + 1);
+
+    for (i = 0, j = 0; i < PA_ELEMENTSOF(all_rates); i++) {
+        if (supported[i])
+            rates[j++] = all_rates[i];
+    }
+
+    rates[j] = 0;
+
+    return rates;
+}
+
 pa_bool_t pa_alsa_pcm_is_hw(snd_pcm_t *pcm) {
     snd_pcm_info_t* info;
     snd_pcm_info_alloca(&info);

src/modules/alsa/alsa-util.h

@@ -133,6 +133,8 @@ char *pa_alsa_get_driver_name_by_pcm(snd_pcm_t *pcm);
 
 char *pa_alsa_get_reserve_name(const char *device);
 
+unsigned int *pa_alsa_get_supported_rates(snd_pcm_t *pcm);
+
 pa_bool_t pa_alsa_pcm_is_hw(snd_pcm_t *pcm);
 pa_bool_t pa_alsa_pcm_is_modem(snd_pcm_t *pcm);