oss code refactoring, sound for frame unlim mode

[libpicofe.git] / linux / sndout_oss.c

diff --git a/linux/sndout_oss.c b/linux/sndout_oss.c
index e2d0bde..ccadbba 100644 (file)
--- a/linux/sndout_oss.c
+++ b/linux/sndout_oss.c
@@ -10,6 +10,8 @@
 #include "sndout_oss.h"
 
 static int sounddev = -1, mixerdev = -1;
+static int can_write_safe;
+
 
 int sndout_oss_init(void)
 {
@@ -23,18 +25,21 @@ int sndout_oss_init(void)
        return 0;
 }
 
-
-int sndout_oss_start(int rate, int bits, int stereo)
+int sndout_oss_start(int rate, int frame_samples, int stereo)
 {
-       static int s_oldrate = 0, s_oldbits = 0, s_oldstereo = 0;
-       int frag = 0, bsize, buffers, ret;
+       static int s_oldrate = 0, s_old_fsamples = 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_oldbits == bits && s_oldstereo == stereo)
+       if (rate == s_oldrate && s_old_fsamples == frame_samples && s_oldstereo == stereo)
                return 0;
 
-       if (sounddev >= 0) close(sounddev);
+       if (sounddev >= 0) {
+               ioctl(sounddev, SOUND_PCM_SYNC, 0);
+               close(sounddev);
+       }
+
        sounddev = open("/dev/dsp", O_WRONLY|O_ASYNC);
        if (sounddev == -1)
        {
@@ -42,42 +47,67 @@ int sndout_oss_start(int rate, int bits, int stereo)
                return -1;
        }
 
-       // calculate buffer size
-       // this is tuned for GP2X
-       buffers = 16;
-       bsize = rate / 32;
-       if (rate > 22050) { bsize*=4; buffers*=2; }
-       while ((bsize>>=1)) frag++;
-       frag |= buffers<<16; // 16 buffers
-       ret = ioctl(sounddev, SNDCTL_DSP_SETFRAGMENT, &frag);
-       if (ret) perror("SNDCTL_DSP_SETFRAGMENT failed");
+       // 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;
+
+       for (frag = 0; bsize; bsize >>= 1, frag++)
+               ;
 
-       ret  = ioctl(sounddev, SNDCTL_DSP_STEREO, &stereo);
-       ret |= ioctl(sounddev, SNDCTL_DSP_SETFMT, &bits);
-       ret |= ioctl(sounddev, SNDCTL_DSP_SPEED,  &rate);
-       if (ret) printf("failed to set audio format\n");
+       frag |= 16 << 16;       // fragment count
+       ret = ioctl(sounddev, SNDCTL_DSP_SETFRAGMENT, &frag);
+       if (ret < 0)
+               perror("SNDCTL_DSP_SETFRAGMENT failed");
+
+       bits = 16;
+       ret = ioctl(sounddev, SNDCTL_DSP_STEREO, &stereo);
+       if (ret == 0)
+               ret = ioctl(sounddev, SNDCTL_DSP_SETFMT, &bits);
+       if (ret == 0)
+               ret = ioctl(sounddev, SNDCTL_DSP_SPEED, &rate);
+       if (ret < 0)
+               perror("failed to set audio format");
+
+       // not sure if this is still needed (avoiding driver bugs?)
        usleep(192*1024);
 
-       printf("gp2x_set_sound: %i/%ibit/%s, %i buffers of %i bytes\n",
-               rate, bits, stereo?"stereo":"mono", frag>>16, 1<<(frag&0xffff));
+       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_oldbits = bits; s_oldstereo = stereo;
+       s_oldrate = rate; s_old_fsamples = frame_samples; s_oldstereo = stereo;
+       can_write_safe = 0;
        return 0;
 }
 
-
 int sndout_oss_write(const void *buff, int len)
 {
        return write(sounddev, buff, len);
 }
 
+int sndout_oss_can_write(int bytes)
+{
+       audio_buf_info bi;
+       int ret;
+
+#ifdef __GP2X__
+       // note: SNDCTL_DSP_GETOSPACE crashes F100 kernel for some reason
+       // if called too early, so we work around here
+       if (can_write_safe++ < 8)
+               return 1;
+#endif
+       ret = ioctl(sounddev, SNDCTL_DSP_GETOSPACE, &bi);
+       if (ret < 0)
+               return 1;
+
+       // have enough bytes to write + 4 extra frags
+       return bi.bytes - bi.fragsize * 4 >= bytes ? 1 : 0;
+}
 
 void sndout_oss_sync(void)
 {
        ioctl(sounddev, SOUND_PCM_SYNC, 0);
 }
 
-
 void sndout_oss_setvol(int l, int r)
 {
        if (mixerdev < 0) return;
@@ -87,7 +117,6 @@ void sndout_oss_setvol(int l, int r)
        ioctl(mixerdev, SOUND_MIXER_WRITE_PCM, &l); /*SOUND_MIXER_WRITE_VOLUME*/
 }
 
-
 void sndout_oss_exit(void)
 {
        if (sounddev >= 0) close(sounddev); sounddev = -1;