1 /* sound output via OSS */
7 #include <sys/soundcard.h>
10 #include "sndout_oss.h"
12 static int sounddev = -1, mixerdev = -1;
13 static int can_write_safe;
17 int sndout_oss_init(void)
19 if (mixerdev >= 0) close(mixerdev);
20 mixerdev = open("/dev/mixer", O_RDWR);
23 perror("open(\"/dev/mixer\")");
29 void sndout_oss_stop(void)
34 ioctl(sounddev, SOUND_PCM_SYNC, 0);
39 int sndout_oss_start(int rate, int stereo, int frames_in_frag)
41 static int s_oldrate = 0, s_oldstereo = 0;
42 int frag, bsize, bits, ret;
44 // GP2X: if no settings change, we don't need to do anything,
45 // since audio is never stopped there
46 if (sounddev >= 0 && rate == s_oldrate && s_oldstereo == stereo)
50 sounddev = open("/dev/dsp", O_WRONLY);
53 perror("open(\"/dev/dsp\")");
54 sounddev = open("/dev/dsp1", O_WRONLY);
56 perror("open(\"/dev/dsp1\")");
61 // try to fit frames_in_frag frames worth of data in fragment
62 // ignore mono because it's unlikely to be used and
63 // both GP2X and Wiz mixes mono to stereo anyway.
64 bsize = (frames_in_frag * rate / 50) * 4;
66 for (frag = 0; bsize; bsize >>= 1, frag++)
69 frag |= FRAG_COUNT << 16; // fragment count
70 ret = ioctl(sounddev, SNDCTL_DSP_SETFRAGMENT, &frag);
72 perror("SNDCTL_DSP_SETFRAGMENT failed");
75 ret = ioctl(sounddev, SNDCTL_DSP_STEREO, &stereo);
77 ret = ioctl(sounddev, SNDCTL_DSP_SETFMT, &bits);
79 ret = ioctl(sounddev, SNDCTL_DSP_SPEED, &rate);
81 perror("failed to set audio format");
84 // not sure if this is still needed (avoiding driver bugs?)
88 printf("sndout_oss_start: %d/%dbit/%s, %d buffers of %i bytes\n",
89 rate, bits, stereo ? "stereo" : "mono", frag >> 16, 1 << (frag & 0xffff));
91 s_oldrate = rate; s_oldstereo = stereo;
96 int sndout_oss_write(const void *buff, int len)
98 return write(sounddev, buff, len);
101 int sndout_oss_can_write(int bytes)
107 // note: SNDCTL_DSP_GETOSPACE crashes F100 kernel for some reason
108 // if called too early, so we work around here
109 if (can_write_safe++ < 8)
112 ret = ioctl(sounddev, SNDCTL_DSP_GETOSPACE, &bi);
116 // have enough bytes to write + 1 frag
117 return bi.bytes - bi.fragsize >= bytes ? 1 : 0;
120 void sndout_oss_sync(void)
122 ioctl(sounddev, SOUND_PCM_SYNC, 0);
125 void sndout_oss_setvol(int l, int r)
127 if (mixerdev < 0) return;
129 l=l<0?0:l; l=l>255?255:l; r=r<0?0:r; r=r>255?255:r;
131 ioctl(mixerdev, SOUND_MIXER_WRITE_PCM, &l); /*SOUND_MIXER_WRITE_VOLUME*/
134 void sndout_oss_exit(void)
136 if (sounddev >= 0) close(sounddev); sounddev = -1;
137 if (mixerdev >= 0) close(mixerdev); mixerdev = -1;