Patch Esound

[Santiago Otero <siryurian terra es>]

Here is a patch for ALSA 0.9 to open audio device in nonblock mode and 
not to hang applications while waiting for audio device. Reading and
writing keep being  blocking. This patch also makes some cleanup in
source code of ALSA.




Index: audio_alsa09.c
===================================================================
RCS file: /cvs/gnome/esound/audio_alsa09.c,v
retrieving revision 1.1
diff -d -u -r1.1 audio_alsa09.c
--- audio_alsa09.c	23 Apr 2002 10:07:57 -0000	1.1
+++ audio_alsa09.c	26 Apr 2002 16:18:26 -0000
@@ -34,7 +34,6 @@
 static char *dev =  "hw:0,0"; 
 
 
-static int framesize = 4;
 
 static snd_output_t *output = NULL;
 
@@ -100,12 +99,13 @@
 	int err;
 	int periods;
   
-	err = snd_pcm_open(&handle, dev, mode, 0);
+	err = snd_pcm_open(&handle, dev, mode, SND_PCM_NONBLOCK);
 	if (err < 0) {
 		if (alsadbg)
 			fprintf(stderr, "%s\n", snd_strerror(err));
 		return NULL;
 	}
+	snd_pcm_nonblock(handle, 0);
 	snd_pcm_hw_params_alloca(&hwparams);
   
 	err = snd_pcm_hw_params_any(handle, hwparams);  
@@ -244,7 +244,6 @@
 			fprintf(stderr, "Device open for capture\n");
 
 	}
-	framesize = snd_pcm_format_physical_width(format) * channels /8;
 	esd_audio_fd = 0;
 	if (alsadbg)
 		print_state();
@@ -279,8 +278,9 @@
 int esd_audio_read( void *buffer, int buf_size )
 {
 	int err;
-  
-	while ( ( err = snd_pcm_readi( alsa_capture_handle, buffer, buf_size/framesize)) < 0) {
+	
+	int len = snd_pcm_bytes_to_frames(alsa_capture_handle, buf_size);
+	while ( ( err = snd_pcm_readi( alsa_capture_handle, buffer, len)) < 0) {
 		if (alsadbg) {
 			fprintf(stderr, "esd_audio_read\n");
 			print_state();
@@ -320,7 +320,7 @@
 		}
 	}
   
-	return (err * framesize);
+	return ( snd_pcm_frames_to_bytes(alsa_capture_handle, err) );
 }
 
 
@@ -328,8 +328,9 @@
 int esd_audio_write( void *buffer, int buf_size )
 {
 	int err;
-  
-	while ( ( err = snd_pcm_writei( alsa_playback_handle, buffer, buf_size/framesize)) < 0) {
+
+	int len = snd_pcm_bytes_to_frames(alsa_playback_handle, buf_size);
+	while ( ( err = snd_pcm_writei( alsa_playback_handle, buffer, len)) < 0) {
 		if (alsadbg) {
 			fprintf(stderr, "esd_audio_write\n");
 			print_state();
@@ -356,15 +357,7 @@
 					return -1;
 			}
 			continue;
-		} else if (err == -EBADFD) {
-			err = snd_pcm_prepare(alsa_playback_handle) ;
-			if (err < 0) {
-				if (alsadbg)
-					fprintf(stderr, "%s\n", snd_strerror(err));
-				return -1;
-			}
-			continue;
-		}
+		} 
 		err = snd_pcm_prepare(alsa_playback_handle) ;
 		if (err < 0) {
 			if (alsadbg)
@@ -373,7 +366,7 @@
 		}
 	}
   
-	return ( err * framesize);
+	return ( snd_pcm_frames_to_bytes(alsa_playback_handle, err) );
 }
 
 #define ARCH_esd_audio_flush