X-Git-Url: https://notaz.gp2x.de/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=linux%2Fsndout_oss.c;h=c0b775aba24b3fa73604bd1766ebaf39918133a3;hb=26d3ca0d29e87a14943d29fcafc93da753df60cd;hp=f74e706d57c817bb0f94ab0d416d8b21516c59cc;hpb=5f7b515538c52c9a4e137f35fe07011e4388a517;p=libpicofe.git

diff --git a/linux/sndout_oss.c b/linux/sndout_oss.c
index f74e706..c0b775a 100644
--- a/linux/sndout_oss.c
+++ b/linux/sndout_oss.c
@@ -1,3 +1,14 @@
+/*
+ * (C) Gražvydas "notaz" Ignotas, 2009-2010
+ *
+ * This work is licensed under the terms of any of these licenses
+ * (at your option):
+ *  - GNU GPL, version 2 or later.
+ *  - GNU LGPL, version 2.1 or later.
+ *  - MAME license.
+ * See the COPYING file in the top-level directory.
+ */
+
 /* sound output via OSS */
 #include <stdio.h>
 #include <sys/types.h>
@@ -9,9 +20,12 @@
 
 #include "sndout_oss.h"
 
+int sndout_oss_frag_frames = 1;
+
 static int sounddev = -1, mixerdev = -1;
 static int can_write_safe;
 
+#define FRAG_COUNT 4
 
 int sndout_oss_init(void)
 {
@@ -25,40 +39,48 @@ int sndout_oss_init(void)
 	return 0;
 }
 
-int sndout_oss_start(int rate, int frame_samples, int stereo)
+void sndout_oss_stop(void)
+{
+	if (sounddev < 0)
+		return;
+
+	ioctl(sounddev, SOUND_PCM_SYNC, 0);
+	close(sounddev);
+	sounddev = -1;
+}
+
+int sndout_oss_start(int rate, int stereo)
 {
-	static int s_oldrate = 0, s_old_fsamples = 0, s_oldstereo = 0;
+	static int s_oldrate = 0, s_oldstereo = 0;
 	int frag, bsize, bits, ret;
 
-	// if no settings change, we don't need to do anything,
-	// since audio is never stopped
-	if (rate == s_oldrate && s_old_fsamples == frame_samples && s_oldstereo == stereo)
+	// GP2X: if no settings change, we don't need to do anything,
+	// since audio is never stopped there
+	if (sounddev >= 0 && rate == s_oldrate && s_oldstereo == stereo)
 		return 0;
 
-	if (sounddev >= 0) {
-		ioctl(sounddev, SOUND_PCM_SYNC, 0);
-		close(sounddev);
-	}
-
-	sounddev = open("/dev/dsp", O_WRONLY|O_ASYNC);
+	sndout_oss_stop();
+	sounddev = open("/dev/dsp", O_WRONLY);
 	if (sounddev == -1)
 	{
 		perror("open(\"/dev/dsp\")");
-		sounddev = open("/dev/dsp1", O_WRONLY|O_ASYNC);
+		sounddev = open("/dev/dsp1", O_WRONLY);
 		if (sounddev == -1) {
 			perror("open(\"/dev/dsp1\")");
 			return -1;
 		}
 	}
 
-	// calculate buffer size. We one to fit 1 frame worth of sound data.
-	// Also ignore mono because both GP2X and Wiz mixes mono to stereo anyway.
-	bsize = frame_samples << 2;
+	// try to fit sndout_oss_frag_frames (video) frames
+	// worth of sound data in OSS fragment
+	// ignore mono because it's unlikely to be used and
+	// both GP2X and Wiz mixes mono to stereo anyway.
+	bsize = (sndout_oss_frag_frames * rate / 50) * 4;
 
 	for (frag = 0; bsize; bsize >>= 1, frag++)
 		;
 
-	frag |= 16 << 16;	// fragment count
+	frag |= FRAG_COUNT << 16;	// fragment count
 	ret = ioctl(sounddev, SNDCTL_DSP_SETFRAGMENT, &frag);
 	if (ret < 0)
 		perror("SNDCTL_DSP_SETFRAGMENT failed");
@@ -72,13 +94,15 @@ int sndout_oss_start(int rate, int frame_samples, int stereo)
 	if (ret < 0)
 		perror("failed to set audio format");
 
+#ifdef __GP2X__
 	// not sure if this is still needed (avoiding driver bugs?)
 	usleep(192*1024);
+#endif
 
 	printf("sndout_oss_start: %d/%dbit/%s, %d buffers of %i bytes\n",
 		rate, bits, stereo ? "stereo" : "mono", frag >> 16, 1 << (frag & 0xffff));
 
-	s_oldrate = rate; s_old_fsamples = frame_samples; s_oldstereo = stereo;
+	s_oldrate = rate; s_oldstereo = stereo;
 	can_write_safe = 0;
 	return 0;
 }
@@ -88,6 +112,42 @@ int sndout_oss_write(const void *buff, int len)
 	return write(sounddev, buff, len);
 }
 
+#include "../plat.h"
+
+/* not really non-blocking, just detects if blocking occurs
+ * and starts skipping writes in case it does. */
+int sndout_oss_write_nb(const void *buff, int len)
+{
+	static int lag_counter, skip_counter;
+	unsigned int t;
+	int ret;
+
+	if (lag_counter > 2) {
+		// skip writes if audio starts blocking
+		lag_counter = 0;
+		skip_counter = FRAG_COUNT;
+	}
+
+	if (skip_counter > 0) {
+		skip_counter--;
+		return len;
+	}
+
+	t = plat_get_ticks_ms();
+	ret = sndout_oss_write(buff, len);
+	t = plat_get_ticks_ms() - t;
+	if (t > 1) {
+		// this shouldn't really happen, most likely audio is out of sync
+		lag_counter++;
+		if (lag_counter > 2)
+			printf("audio lag %u\n", t);
+	}
+	else
+		lag_counter = 0;
+
+	return ret;
+}
+
 int sndout_oss_can_write(int bytes)
 {
 	audio_buf_info bi;
@@ -103,12 +163,13 @@ int sndout_oss_can_write(int bytes)
 	if (ret < 0)
 		return 1;
 
-	// have enough bytes to write + 4 extra frags
-	return bi.bytes - bi.fragsize * 4 >= bytes ? 1 : 0;
+	// have enough bytes to write + 1 frag
+	return bi.bytes - bi.fragsize >= bytes ? 1 : 0;
 }
 
-void sndout_oss_sync(void)
+void sndout_oss_wait(void)
 {
+	// FIXME?
 	ioctl(sounddev, SOUND_PCM_SYNC, 0);
 }