option to use ALSA default fragment number and size

git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@295 fefdeb5f-60dc-0310-8127-8f9354f1896f

1 files changed, 27 insertions, 8 deletions

diff --git a/polyp/alsa-util.c b/polyp/alsa-util.c
index 188ba077..eaa21d49 100644
--- a/polyp/alsa-util.c
+++ b/polyp/alsa-util.c
@@ -30,8 +30,9 @@
 #include "sample.h"
 #include "xmalloc.h"
 
-int pa_alsa_set_hw_params(snd_pcm_t *pcm_handle, struct pa_sample_spec *ss, uint32_t *periods, snd_pcm_uframes_t *buffer_size) {
-    int ret = 0;
+int pa_alsa_set_hw_params(snd_pcm_t *pcm_handle, struct pa_sample_spec *ss, uint32_t *periods, snd_pcm_uframes_t *period_size) {
+    int ret = -1;
+    snd_pcm_uframes_t buffer_size;
     snd_pcm_hw_params_t *hwparams = NULL;
     static const snd_pcm_format_t format_trans[] = {
         [PA_SAMPLE_U8] = SND_PCM_FORMAT_U8,
@@ -42,21 +43,39 @@ int pa_alsa_set_hw_params(snd_pcm_t *pcm_handle, struct pa_sample_spec *ss, uint
         [PA_SAMPLE_FLOAT32LE] = SND_PCM_FORMAT_FLOAT_LE,
         [PA_SAMPLE_FLOAT32BE] = SND_PCM_FORMAT_FLOAT_BE,
     };
-
+    assert(pcm_handle && ss && periods && period_size);
+    
     if (snd_pcm_hw_params_malloc(&hwparams) < 0 ||
         snd_pcm_hw_params_any(pcm_handle, hwparams) < 0 ||
         snd_pcm_hw_params_set_access(pcm_handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED) < 0 ||
         snd_pcm_hw_params_set_format(pcm_handle, hwparams, format_trans[ss->format]) < 0 ||
         snd_pcm_hw_params_set_rate_near(pcm_handle, hwparams, &ss->rate, NULL) < 0 ||
         snd_pcm_hw_params_set_channels(pcm_handle, hwparams, ss->channels) < 0 ||
-        snd_pcm_hw_params_set_periods_near(pcm_handle, hwparams, periods, NULL) < 0 || 
-        snd_pcm_hw_params_set_buffer_size_near(pcm_handle, hwparams, buffer_size) < 0 || 
-        snd_pcm_hw_params(pcm_handle, hwparams) < 0) {
-        ret = -1;
-    }
+        (*periods > 0 && snd_pcm_hw_params_set_periods_near(pcm_handle, hwparams, periods, NULL) < 0) || 
+        (*period_size > 0 && snd_pcm_hw_params_set_period_size_near(pcm_handle, hwparams, period_size, NULL) < 0) || 
+        snd_pcm_hw_params(pcm_handle, hwparams) < 0)
+        goto finish;
+    
+    if (snd_pcm_prepare(pcm_handle) < 0)
+        goto finish;
 
+    if (snd_pcm_hw_params_current(pcm_handle, hwparams) < 0)
+        goto finish;
+    
+    if (snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size) < 0 ||
+        snd_pcm_hw_params_get_period_size(hwparams, period_size, NULL) < 0)
+        goto finish;
+
+    assert(buffer_size > 0 && *period_size > 0);
+    *periods = buffer_size / *period_size;
+    assert(*periods > 0);
+    
+    ret = 0;
+    
+finish:
     if (hwparams)
         snd_pcm_hw_params_free(hwparams);
+    
     return ret;
 }