Reverted to the version of audio_pipe.c prior to the last major change and used a different method to open the pipe for writing.

audio_pipe.c

@@ -28,98 +28,58 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <memory.h>
-#include <errno.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/time.h>
 #include "common.h"
 #include "audio.h"
 
 static int fd = -1;
 static char *pipename = NULL;
 static int Fs;
-static long long starttime, samples_played;
-
-static void stop(void) {
-    close(fd);
-    fd = -1;
-}
 
 static void start(int sample_rate) {
-    if (fd >= 0)
-        stop();
-
-    fd = open(pipename, O_WRONLY | O_NONBLOCK);
-    if ((fd < 0) && (errno != ENXIO)) {
+	int readfd;
+
+	Fs = sample_rate;
+
+	readfd = open(pipename, O_RDONLY | O_NONBLOCK);
+	if (readfd < 0) {
+		perror("open");
+		die("could not open specified pipe for reading");
+	}
+	fd = open(pipename, O_WRONLY);
+	if (fd < 0) {
         perror("open");
         die("could not open specified pipe for writing");
     }
-
-    // The other end is ready, reopen with blocking
-    if (fd >= 0) {
-        close(fd);
-        fd = open(pipename, O_WRONLY);
-    }
-
-    Fs = sample_rate;
-    starttime = 0;
-    samples_played = 0;
-}
-
-// Wait procedure taken from audio_dummy.c
-static void wait_samples(int samples) {
-    struct timeval tv;
-
-    // this is all a bit expensive but it's long-term stable.
-    gettimeofday(&tv, NULL);
-
-    long long nowtime = tv.tv_usec + 1e6*tv.tv_sec;
-
-    if (!starttime)
-        starttime = nowtime;
-
-    samples_played += samples;
-
-    long long finishtime = starttime + samples_played * 1e6 / Fs;
-
-    usleep(finishtime - nowtime);
+	close(readfd);
 }
 
 static void play(short buf[], int samples) {
-    if (fd < 0) {
-        wait_samples(samples);
-
-        // check if the other end is ready every 5 seconds
-        if (samples_played > 5 * Fs)
-            start(Fs);
-
-        return;
-    }
+	int rc;
+
+	rc = write(fd, buf, samples*4);
+	if (rc <=0) usleep(1e6 * samples / Fs);
+}
 
-    if (write(fd, buf, samples*4) < 0)
-        stop();
+static void stop(void) {
+	close(fd);
 }
 
 static int init(int argc, char **argv) {
-    struct stat sb;
-
     if (argc != 1)
         die("bad argument(s) to pipe");
 
     pipename = strdup(argv[0]);
 
-    if (stat(pipename, &sb) < 0)
-        die("could not stat() pipe");
-
-    if (!S_ISFIFO(sb.st_mode))
-        die("not a pipe");
-
+	// test open pipe so we error on startup if it's going to fail
+	start(44100);
+	stop();
+
     return 0;
 }
 
 static void deinit(void) {
-    if (fd >= 0)
-        stop();
+    if (fd > 0)
+        close(fd);
     if (pipename)
         free(pipename);
 }