Cleanup ALSA mic initialization

ALSA microphone code still suck but now a little bit less.
Cleanup the initialization:
- use default device
- don't force a buffer size and a period which some drivers
can't support, instead query the driver for them

The next step would be to add use interrupt driven capturing
on a separathe thread but ALSA is a bitch...

desmume/src/mic_alsa.cpp

@@ -36,72 +36,67 @@ u8 Mic_WriteBuf;
 
 int MicButtonPressed;
 
-// Handle for the PCM device
+/* Alsa stuff */
 static snd_pcm_t *pcm_handle;
 
 BOOL Mic_Init()
 {
     snd_pcm_hw_params_t *hwparams;
+    snd_pcm_uframes_t mic_bufsize, periods;
     int err;
 
     if (Mic_Inited)
         return TRUE;
 
-    // Open the default sound card in capture
+    if ((err = snd_pcm_open(&pcm_handle, "default", SND_PCM_STREAM_CAPTURE, SND_PCM_NONBLOCK)) < 0) {
-    if ((err = snd_pcm_open(&pcm_handle, "plughw:0,0", SND_PCM_STREAM_CAPTURE, SND_PCM_NONBLOCK)) < 0) {
         g_printerr("Failed to open device: %s\n", snd_strerror(err));
         return FALSE;
     }
 
-    // Allocate the snd_pcm_hw_params_t structure and fill it.
+    /* Hardware params */
     snd_pcm_hw_params_alloca(&hwparams);
     if ((err = snd_pcm_hw_params_any(pcm_handle, hwparams)) < 0) {
         g_printerr("Failed to setup hw parameters: %s\n", snd_strerror(err));
         return FALSE;
     }
 
-    //Set the access
     if ((err = snd_pcm_hw_params_set_access(pcm_handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
         g_printerr("Failed to set access: %s\n", snd_strerror(err));
         return FALSE;
     }
 
-    //dir 0 == exacte (Rate = 16K exacte)
+    /* 8bit signed, mono, 16000hz */
-    if ((err = snd_pcm_hw_params_set_rate(pcm_handle, hwparams, 16000, 0)) < 0) {
-        g_printerr("Failed to set rate: %s\n", snd_strerror(err));
-        return FALSE;
-    }
-
-    /* Set sample format */
     if ((err = snd_pcm_hw_params_set_format(pcm_handle, hwparams, SND_PCM_FORMAT_S8)) < 0) {
         g_printerr("Failed to set format: %s\n", snd_strerror(err));
         return FALSE;
     }
 
-    // Set one channel (mono)
     if ((err = snd_pcm_hw_params_set_channels(pcm_handle, hwparams, 1)) < 0) {
         g_printerr("Failed to set channels: %s\n", snd_strerror(err));
         return FALSE;
     }
 
-    // Set 2 periods
+    if ((err = snd_pcm_hw_params_set_rate(pcm_handle, hwparams, 16000, 0)) < 0) {
-    if ((err = snd_pcm_hw_params_set_periods(pcm_handle, hwparams, 2, 0)) < 0) {
+        g_printerr("Failed to set rate: %s\n", snd_strerror(err));
-        g_printerr("Failed to set periods: %s\n", snd_strerror(err));
         return FALSE;
     }
 
-    // Set the buffer sise
-    if ((err = snd_pcm_hw_params_set_buffer_size(pcm_handle, hwparams, MIC_BUFSIZE)) < 0) {
-        g_printerr("Failed to set buffer size: %s\n", snd_strerror(err));
-        return FALSE;
-    }
-
-    //Set the params
     if ((err = snd_pcm_hw_params(pcm_handle, hwparams)) < 0) {
         g_printerr("Failed to set hw parameters: %s\n", snd_strerror(err));
         return FALSE;
     }
 
+    /* Query the driver for buffer and period sizes */
+    if ((err = snd_pcm_hw_params_get_buffer_size(hwparams, &mic_bufsize)) < 0) {
+        g_printerr("Failed to get buffer size: %s\n", snd_strerror(err));
+        return FALSE;
+    }
+
+    if ((err = snd_pcm_hw_params_get_period_size(hwparams, &periods, 0)) < 0) {
+        g_printerr("Failed to get period size: %s\n", snd_strerror(err));
+        return FALSE;
+    }
+
     Mic_Inited = TRUE;
     Mic_Reset();