src/audio/dma/SDL_dmaaudio.c
branchSDL-1.3
changeset 1662 782fd950bd46
parent 1402 d910939febfa
child 1668 4da1ee79c9af
--- a/src/audio/dma/SDL_dmaaudio.c	Sun May 21 17:27:13 2006 +0000
+++ b/src/audio/dma/SDL_dmaaudio.c	Sun May 28 13:04:16 2006 +0000
@@ -24,7 +24,7 @@
 /* Allow access to a raw mixing buffer */
 
 #include <stdio.h>
-#include <string.h>	/* For strerror() */
+#include <string.h>             /* For strerror() */
 #include <errno.h>
 #include <unistd.h>
 #include <fcntl.h>
@@ -60,396 +60,410 @@
 #define OPEN_FLAGS	(O_RDWR|O_NONBLOCK)
 
 /* Audio driver functions */
-static int DMA_OpenAudio(_THIS, SDL_AudioSpec *spec);
-static void DMA_WaitAudio(_THIS);
-static void DMA_PlayAudio(_THIS);
-static Uint8 *DMA_GetAudioBuf(_THIS);
-static void DMA_CloseAudio(_THIS);
+static int DMA_OpenAudio (_THIS, SDL_AudioSpec * spec);
+static void DMA_WaitAudio (_THIS);
+static void DMA_PlayAudio (_THIS);
+static Uint8 *DMA_GetAudioBuf (_THIS);
+static void DMA_CloseAudio (_THIS);
 
 /* Audio driver bootstrap functions */
 
-static int Audio_Available(void)
+static int
+Audio_Available (void)
 {
-	int available;
-	int fd;
+    int available;
+    int fd;
 
-	available = 0;
+    available = 0;
 
-	fd = SDL_OpenAudioPath(NULL, 0, OPEN_FLAGS, 0);
-	if ( fd >= 0 ) {
-		int caps;
-		struct audio_buf_info info;
+    fd = SDL_OpenAudioPath (NULL, 0, OPEN_FLAGS, 0);
+    if (fd >= 0) {
+        int caps;
+        struct audio_buf_info info;
 
-		if ( (ioctl(fd, SNDCTL_DSP_GETCAPS, &caps) == 0) &&
-	             (caps & DSP_CAP_TRIGGER) && (caps & DSP_CAP_MMAP) &&
-		     (ioctl(fd, SNDCTL_DSP_GETOSPACE, &info) == 0) ) {
-			available = 1;
-		}
-		close(fd);
-	}
-	return(available);
+        if ((ioctl (fd, SNDCTL_DSP_GETCAPS, &caps) == 0) &&
+            (caps & DSP_CAP_TRIGGER) && (caps & DSP_CAP_MMAP) &&
+            (ioctl (fd, SNDCTL_DSP_GETOSPACE, &info) == 0)) {
+            available = 1;
+        }
+        close (fd);
+    }
+    return (available);
 }
 
-static void Audio_DeleteDevice(SDL_AudioDevice *device)
+static void
+Audio_DeleteDevice (SDL_AudioDevice * device)
 {
-	SDL_free(device->hidden);
-	SDL_free(device);
+    SDL_free (device->hidden);
+    SDL_free (device);
 }
 
-static SDL_AudioDevice *Audio_CreateDevice(int devindex)
+static SDL_AudioDevice *
+Audio_CreateDevice (int devindex)
 {
-	SDL_AudioDevice *this;
+    SDL_AudioDevice *this;
 
-	/* Initialize all variables that we clean on shutdown */
-	this = (SDL_AudioDevice *)SDL_malloc(sizeof(SDL_AudioDevice));
-	if ( this ) {
-		SDL_memset(this, 0, (sizeof *this));
-		this->hidden = (struct SDL_PrivateAudioData *)
-				SDL_malloc((sizeof *this->hidden));
-	}
-	if ( (this == NULL) || (this->hidden == NULL) ) {
-		SDL_OutOfMemory();
-		if ( this ) {
-			SDL_free(this);
-		}
-		return(0);
-	}
-	SDL_memset(this->hidden, 0, (sizeof *this->hidden));
-	audio_fd = -1;
+    /* Initialize all variables that we clean on shutdown */
+    this = (SDL_AudioDevice *) SDL_malloc (sizeof (SDL_AudioDevice));
+    if (this) {
+        SDL_memset (this, 0, (sizeof *this));
+        this->hidden = (struct SDL_PrivateAudioData *)
+            SDL_malloc ((sizeof *this->hidden));
+    }
+    if ((this == NULL) || (this->hidden == NULL)) {
+        SDL_OutOfMemory ();
+        if (this) {
+            SDL_free (this);
+        }
+        return (0);
+    }
+    SDL_memset (this->hidden, 0, (sizeof *this->hidden));
+    audio_fd = -1;
 
-	/* Set the function pointers */
-	this->OpenAudio = DMA_OpenAudio;
-	this->WaitAudio = DMA_WaitAudio;
-	this->PlayAudio = DMA_PlayAudio;
-	this->GetAudioBuf = DMA_GetAudioBuf;
-	this->CloseAudio = DMA_CloseAudio;
+    /* Set the function pointers */
+    this->OpenAudio = DMA_OpenAudio;
+    this->WaitAudio = DMA_WaitAudio;
+    this->PlayAudio = DMA_PlayAudio;
+    this->GetAudioBuf = DMA_GetAudioBuf;
+    this->CloseAudio = DMA_CloseAudio;
 
-	this->free = Audio_DeleteDevice;
+    this->free = Audio_DeleteDevice;
 
-	return this;
+    return this;
 }
 
 AudioBootStrap DMA_bootstrap = {
-	DMA_DRIVER_NAME, "OSS /dev/dsp DMA audio",
-	Audio_Available, Audio_CreateDevice
+    DMA_DRIVER_NAME, "OSS /dev/dsp DMA audio",
+    Audio_Available, Audio_CreateDevice
 };
 
 /* This function waits until it is possible to write a full sound buffer */
-static void DMA_WaitAudio(_THIS)
+static void
+DMA_WaitAudio (_THIS)
 {
-	fd_set fdset;
+    fd_set fdset;
 
-	/* Check to see if the thread-parent process is still alive */
-	{ static int cnt = 0;
-		/* Note that this only works with thread implementations 
-		   that use a different process id for each thread.
-		*/
-		if (parent && (((++cnt)%10) == 0)) { /* Check every 10 loops */
-			if ( kill(parent, 0) < 0 ) {
-				this->enabled = 0;
-			}
-		}
-	}
+    /* Check to see if the thread-parent process is still alive */
+    {
+        static int cnt = 0;
+        /* Note that this only works with thread implementations 
+           that use a different process id for each thread.
+         */
+        if (parent && (((++cnt) % 10) == 0)) {  /* Check every 10 loops */
+            if (kill (parent, 0) < 0) {
+                this->enabled = 0;
+            }
+        }
+    }
 
-	/* See if we need to use timed audio synchronization */
-	if ( frame_ticks ) {
-		/* Use timer for general audio synchronization */
-		Sint32 ticks;
+    /* See if we need to use timed audio synchronization */
+    if (frame_ticks) {
+        /* Use timer for general audio synchronization */
+        Sint32 ticks;
 
-		ticks = ((Sint32)(next_frame - SDL_GetTicks()))-FUDGE_TICKS;
-		if ( ticks > 0 ) {
-			SDL_Delay(ticks);
-		}
-	} else {
-		/* Use select() for audio synchronization */
-		struct timeval timeout;
-		FD_ZERO(&fdset);
-		FD_SET(audio_fd, &fdset);
-		timeout.tv_sec = 10;
-		timeout.tv_usec = 0;
+        ticks = ((Sint32) (next_frame - SDL_GetTicks ())) - FUDGE_TICKS;
+        if (ticks > 0) {
+            SDL_Delay (ticks);
+        }
+    } else {
+        /* Use select() for audio synchronization */
+        struct timeval timeout;
+        FD_ZERO (&fdset);
+        FD_SET (audio_fd, &fdset);
+        timeout.tv_sec = 10;
+        timeout.tv_usec = 0;
 #ifdef DEBUG_AUDIO
-		fprintf(stderr, "Waiting for audio to get ready\n");
+        fprintf (stderr, "Waiting for audio to get ready\n");
 #endif
-		if ( select(audio_fd+1, NULL, &fdset, NULL, &timeout) <= 0 ) {
-			const char *message =
+        if (select (audio_fd + 1, NULL, &fdset, NULL, &timeout) <= 0) {
+            const char *message =
 #ifdef AUDIO_OSPACE_HACK
-			"Audio timeout - buggy audio driver? (trying ospace)";
+                "Audio timeout - buggy audio driver? (trying ospace)";
 #else
-			"Audio timeout - buggy audio driver? (disabled)";
+                "Audio timeout - buggy audio driver? (disabled)";
 #endif
-			/* In general we should never print to the screen,
-			   but in this case we have no other way of letting
-			   the user know what happened.
-			*/
-			fprintf(stderr, "SDL: %s\n", message);
+            /* In general we should never print to the screen,
+               but in this case we have no other way of letting
+               the user know what happened.
+             */
+            fprintf (stderr, "SDL: %s\n", message);
 #ifdef AUDIO_OSPACE_HACK
-			/* We may be able to use GET_OSPACE trick */
-			frame_ticks = (float)(this->spec->samples*1000) /
-			                      this->spec->freq;
-			next_frame = SDL_GetTicks()+frame_ticks;
+            /* We may be able to use GET_OSPACE trick */
+            frame_ticks = (float) (this->spec->samples * 1000) /
+                this->spec->freq;
+            next_frame = SDL_GetTicks () + frame_ticks;
 #else
-			this->enabled = 0;
-			/* Don't try to close - may hang */
-			audio_fd = -1;
+            this->enabled = 0;
+            /* Don't try to close - may hang */
+            audio_fd = -1;
 #ifdef DEBUG_AUDIO
-			fprintf(stderr, "Done disabling audio\n");
+            fprintf (stderr, "Done disabling audio\n");
 #endif
 #endif /* AUDIO_OSPACE_HACK */
-		}
+        }
 #ifdef DEBUG_AUDIO
-		fprintf(stderr, "Ready!\n");
+        fprintf (stderr, "Ready!\n");
 #endif
-	}
+    }
 }
 
-static void DMA_PlayAudio(_THIS)
+static void
+DMA_PlayAudio (_THIS)
 {
-	/* If timer synchronization is enabled, set the next write frame */
-	if ( frame_ticks ) {
-		next_frame += frame_ticks;
-	}
-	return;
+    /* If timer synchronization is enabled, set the next write frame */
+    if (frame_ticks) {
+        next_frame += frame_ticks;
+    }
+    return;
 }
 
-static Uint8 *DMA_GetAudioBuf(_THIS)
+static Uint8 *
+DMA_GetAudioBuf (_THIS)
 {
-	count_info info;
-	int playing;
-	int filling;
+    count_info info;
+    int playing;
+    int filling;
 
-	/* Get number of blocks, looping if we're not using select() */
-	do {
-		if ( ioctl(audio_fd, SNDCTL_DSP_GETOPTR, &info) < 0 ) {
-			/* Uh oh... */
-			this->enabled = 0;
-			return(NULL);
-		}
-	} while ( frame_ticks && (info.blocks < 1) );
+    /* Get number of blocks, looping if we're not using select() */
+    do {
+        if (ioctl (audio_fd, SNDCTL_DSP_GETOPTR, &info) < 0) {
+            /* Uh oh... */
+            this->enabled = 0;
+            return (NULL);
+        }
+    }
+    while (frame_ticks && (info.blocks < 1));
 #ifdef DEBUG_AUDIO
-	if ( info.blocks > 1 ) {
-		printf("Warning: audio underflow (%d frags)\n", info.blocks-1);
-	}
+    if (info.blocks > 1) {
+        printf ("Warning: audio underflow (%d frags)\n", info.blocks - 1);
+    }
 #endif
-	playing = info.ptr / this->spec.size;
-	filling = (playing + 1)%num_buffers;
-	return (dma_buf + (filling * this->spec.size));
+    playing = info.ptr / this->spec.size;
+    filling = (playing + 1) % num_buffers;
+    return (dma_buf + (filling * this->spec.size));
 }
 
-static void DMA_CloseAudio(_THIS)
+static void
+DMA_CloseAudio (_THIS)
 {
-	if ( dma_buf != NULL ) {
-		munmap(dma_buf, dma_len);
-		dma_buf = NULL;
-	}
-	if ( audio_fd >= 0 ) {
-		close(audio_fd);
-		audio_fd = -1;
-	}
+    if (dma_buf != NULL) {
+        munmap (dma_buf, dma_len);
+        dma_buf = NULL;
+    }
+    if (audio_fd >= 0) {
+        close (audio_fd);
+        audio_fd = -1;
+    }
 }
 
-static int DMA_ReopenAudio(_THIS, const char *audiodev, int format, int stereo,
-							SDL_AudioSpec *spec)
+static int
+DMA_ReopenAudio (_THIS, const char *audiodev, int format, int stereo,
+                 SDL_AudioSpec * spec)
 {
-	int frag_spec;
-	int value;
+    int frag_spec;
+    int value;
 
-	/* Close and then reopen the audio device */
-	close(audio_fd);
-	audio_fd = open(audiodev, O_RDWR, 0);
-	if ( audio_fd < 0 ) {
-		SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno));
-		return(-1);
-	}
+    /* Close and then reopen the audio device */
+    close (audio_fd);
+    audio_fd = open (audiodev, O_RDWR, 0);
+    if (audio_fd < 0) {
+        SDL_SetError ("Couldn't open %s: %s", audiodev, strerror (errno));
+        return (-1);
+    }
 
-	/* Calculate the final parameters for this audio specification */
-	SDL_CalculateAudioSpec(spec);
+    /* Calculate the final parameters for this audio specification */
+    SDL_CalculateAudioSpec (spec);
 
-	/* Determine the power of two of the fragment size */
-	for ( frag_spec = 0; (0x01<<frag_spec) < spec->size; ++frag_spec );
-	if ( (0x01<<frag_spec) != spec->size ) {
-		SDL_SetError("Fragment size must be a power of two");
-		return(-1);
-	}
+    /* Determine the power of two of the fragment size */
+    for (frag_spec = 0; (0x01 << frag_spec) < spec->size; ++frag_spec);
+    if ((0x01 << frag_spec) != spec->size) {
+        SDL_SetError ("Fragment size must be a power of two");
+        return (-1);
+    }
 
-	/* Set the audio buffering parameters */
-	if ( ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &frag_spec) < 0 ) {
-		SDL_SetError("Couldn't set audio fragment spec");
-		return(-1);
-	}
+    /* Set the audio buffering parameters */
+    if (ioctl (audio_fd, SNDCTL_DSP_SETFRAGMENT, &frag_spec) < 0) {
+        SDL_SetError ("Couldn't set audio fragment spec");
+        return (-1);
+    }
 
-	/* Set the audio format */
-	value = format;
-	if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) ||
-						(value != format) ) {
-		SDL_SetError("Couldn't set audio format");
-		return(-1);
-	}
+    /* Set the audio format */
+    value = format;
+    if ((ioctl (audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) ||
+        (value != format)) {
+        SDL_SetError ("Couldn't set audio format");
+        return (-1);
+    }
 
-	/* Set mono or stereo audio */
-	value = (spec->channels > 1);
-	if ( (ioctl(audio_fd, SNDCTL_DSP_STEREO, &stereo) < 0) ||
-						(value != stereo) ) {
-		SDL_SetError("Couldn't set audio channels");
-		return(-1);
-	}
+    /* Set mono or stereo audio */
+    value = (spec->channels > 1);
+    if ((ioctl (audio_fd, SNDCTL_DSP_STEREO, &stereo) < 0) ||
+        (value != stereo)) {
+        SDL_SetError ("Couldn't set audio channels");
+        return (-1);
+    }
 
-	/* Set the DSP frequency */
-	value = spec->freq;
-	if ( ioctl(audio_fd, SNDCTL_DSP_SPEED, &value) < 0 ) {
-		SDL_SetError("Couldn't set audio frequency");
-		return(-1);
-	}
-	spec->freq = value;
+    /* Set the DSP frequency */
+    value = spec->freq;
+    if (ioctl (audio_fd, SNDCTL_DSP_SPEED, &value) < 0) {
+        SDL_SetError ("Couldn't set audio frequency");
+        return (-1);
+    }
+    spec->freq = value;
 
-	/* We successfully re-opened the audio */
-	return(0);
+    /* We successfully re-opened the audio */
+    return (0);
 }
 
-static int DMA_OpenAudio(_THIS, SDL_AudioSpec *spec)
+static int
+DMA_OpenAudio (_THIS, SDL_AudioSpec * spec)
 {
-	char audiodev[1024];
-	int format;
-	int stereo;
-	int value;
-	Uint16 test_format;
-	struct audio_buf_info info;
+    char audiodev[1024];
+    int format;
+    int stereo;
+    int value;
+    Uint16 test_format;
+    struct audio_buf_info info;
 
-	/* Reset the timer synchronization flag */
-	frame_ticks = 0.0;
+    /* Reset the timer synchronization flag */
+    frame_ticks = 0.0;
 
-	/* Open the audio device */
-	audio_fd = SDL_OpenAudioPath(audiodev, sizeof(audiodev), OPEN_FLAGS, 0);
-	if ( audio_fd < 0 ) {
-		SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno));
-		return(-1);
-	}
-	dma_buf = NULL;
-	ioctl(audio_fd, SNDCTL_DSP_RESET, 0);
+    /* Open the audio device */
+    audio_fd = SDL_OpenAudioPath (audiodev, sizeof (audiodev), OPEN_FLAGS, 0);
+    if (audio_fd < 0) {
+        SDL_SetError ("Couldn't open %s: %s", audiodev, strerror (errno));
+        return (-1);
+    }
+    dma_buf = NULL;
+    ioctl (audio_fd, SNDCTL_DSP_RESET, 0);
 
-	/* Get a list of supported hardware formats */
-	if ( ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &value) < 0 ) {
-		SDL_SetError("Couldn't get audio format list");
-		return(-1);
-	}
+    /* Get a list of supported hardware formats */
+    if (ioctl (audio_fd, SNDCTL_DSP_GETFMTS, &value) < 0) {
+        SDL_SetError ("Couldn't get audio format list");
+        return (-1);
+    }
 
-	/* Try for a closest match on audio format */
-	format = 0;
-	for ( test_format = SDL_FirstAudioFormat(spec->format);
-						! format && test_format; ) {
+    /* Try for a closest match on audio format */
+    format = 0;
+    for (test_format = SDL_FirstAudioFormat (spec->format);
+         !format && test_format;) {
 #ifdef DEBUG_AUDIO
-		fprintf(stderr, "Trying format 0x%4.4x\n", test_format);
+        fprintf (stderr, "Trying format 0x%4.4x\n", test_format);
 #endif
-		switch ( test_format ) {
-			case AUDIO_U8:
-				if ( value & AFMT_U8 ) {
-					format = AFMT_U8;
-				}
-				break;
-			case AUDIO_S8:
-				if ( value & AFMT_S8 ) {
-					format = AFMT_S8;
-				}
-				break;
-			case AUDIO_S16LSB:
-				if ( value & AFMT_S16_LE ) {
-					format = AFMT_S16_LE;
-				}
-				break;
-			case AUDIO_S16MSB:
-				if ( value & AFMT_S16_BE ) {
-					format = AFMT_S16_BE;
-				}
-				break;
-			case AUDIO_U16LSB:
-				if ( value & AFMT_U16_LE ) {
-					format = AFMT_U16_LE;
-				}
-				break;
-			case AUDIO_U16MSB:
-				if ( value & AFMT_U16_BE ) {
-					format = AFMT_U16_BE;
-				}
-				break;
-			default:
-				format = 0;
-				break;
-		}
-		if ( ! format ) {
-			test_format = SDL_NextAudioFormat();
-		}
-	}
-	if ( format == 0 ) {
-		SDL_SetError("Couldn't find any hardware audio formats");
-		return(-1);
-	}
-	spec->format = test_format;
+        switch (test_format) {
+        case AUDIO_U8:
+            if (value & AFMT_U8) {
+                format = AFMT_U8;
+            }
+            break;
+        case AUDIO_S8:
+            if (value & AFMT_S8) {
+                format = AFMT_S8;
+            }
+            break;
+        case AUDIO_S16LSB:
+            if (value & AFMT_S16_LE) {
+                format = AFMT_S16_LE;
+            }
+            break;
+        case AUDIO_S16MSB:
+            if (value & AFMT_S16_BE) {
+                format = AFMT_S16_BE;
+            }
+            break;
+        case AUDIO_U16LSB:
+            if (value & AFMT_U16_LE) {
+                format = AFMT_U16_LE;
+            }
+            break;
+        case AUDIO_U16MSB:
+            if (value & AFMT_U16_BE) {
+                format = AFMT_U16_BE;
+            }
+            break;
+        default:
+            format = 0;
+            break;
+        }
+        if (!format) {
+            test_format = SDL_NextAudioFormat ();
+        }
+    }
+    if (format == 0) {
+        SDL_SetError ("Couldn't find any hardware audio formats");
+        return (-1);
+    }
+    spec->format = test_format;
 
-	/* Set the audio format */
-	value = format;
-	if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) ||
-						(value != format) ) {
-		SDL_SetError("Couldn't set audio format");
-		return(-1);
-	}
+    /* Set the audio format */
+    value = format;
+    if ((ioctl (audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) ||
+        (value != format)) {
+        SDL_SetError ("Couldn't set audio format");
+        return (-1);
+    }
 
-	/* Set mono or stereo audio (currently only two channels supported) */
-	stereo = (spec->channels > 1);
-	ioctl(audio_fd, SNDCTL_DSP_STEREO, &stereo);
-	if ( stereo ) {
-		spec->channels = 2;
-	} else {
-		spec->channels = 1;
-	}
+    /* Set mono or stereo audio (currently only two channels supported) */
+    stereo = (spec->channels > 1);
+    ioctl (audio_fd, SNDCTL_DSP_STEREO, &stereo);
+    if (stereo) {
+        spec->channels = 2;
+    } else {
+        spec->channels = 1;
+    }
 
-	/* Because some drivers don't allow setting the buffer size
-	   after setting the format, we must re-open the audio device
-	   once we know what format and channels are supported
-	 */
-	if ( DMA_ReopenAudio(this, audiodev, format, stereo, spec) < 0 ) {
-		/* Error is set by DMA_ReopenAudio() */
-		return(-1);
-	}
+    /* Because some drivers don't allow setting the buffer size
+       after setting the format, we must re-open the audio device
+       once we know what format and channels are supported
+     */
+    if (DMA_ReopenAudio (this, audiodev, format, stereo, spec) < 0) {
+        /* Error is set by DMA_ReopenAudio() */
+        return (-1);
+    }
 
-	/* Memory map the audio buffer */
-	if ( ioctl(audio_fd, SNDCTL_DSP_GETOSPACE, &info) < 0 ) {
-		SDL_SetError("Couldn't get OSPACE parameters");
-		return(-1);
-	}
-	spec->size = info.fragsize;
-	spec->samples = spec->size / ((spec->format & 0xFF) / 8);
-	spec->samples /= spec->channels;
-	num_buffers = info.fragstotal;
-	dma_len = num_buffers*spec->size;
-	dma_buf = (Uint8 *)mmap(NULL, dma_len, PROT_WRITE, MAP_SHARED,
-							audio_fd, 0);
-	if ( dma_buf == MAP_FAILED ) {
-		SDL_SetError("DMA memory map failed");
-		dma_buf = NULL;
-		return(-1);
-	}
-	SDL_memset(dma_buf, spec->silence, dma_len);
+    /* Memory map the audio buffer */
+    if (ioctl (audio_fd, SNDCTL_DSP_GETOSPACE, &info) < 0) {
+        SDL_SetError ("Couldn't get OSPACE parameters");
+        return (-1);
+    }
+    spec->size = info.fragsize;
+    spec->samples = spec->size / ((spec->format & 0xFF) / 8);
+    spec->samples /= spec->channels;
+    num_buffers = info.fragstotal;
+    dma_len = num_buffers * spec->size;
+    dma_buf = (Uint8 *) mmap (NULL, dma_len, PROT_WRITE, MAP_SHARED,
+                              audio_fd, 0);
+    if (dma_buf == MAP_FAILED) {
+        SDL_SetError ("DMA memory map failed");
+        dma_buf = NULL;
+        return (-1);
+    }
+    SDL_memset (dma_buf, spec->silence, dma_len);
 
-	/* Check to see if we need to use select() workaround */
-	{ char *workaround;
-		workaround = SDL_getenv("SDL_DSP_NOSELECT");
-		if ( workaround ) {
-			frame_ticks = (float)(spec->samples*1000)/spec->freq;
-			next_frame = SDL_GetTicks()+frame_ticks;
-		}
-	}
+    /* Check to see if we need to use select() workaround */
+    {
+        char *workaround;
+        workaround = SDL_getenv ("SDL_DSP_NOSELECT");
+        if (workaround) {
+            frame_ticks = (float) (spec->samples * 1000) / spec->freq;
+            next_frame = SDL_GetTicks () + frame_ticks;
+        }
+    }
 
-	/* Trigger audio playback */
-	value = 0;
-	ioctl(audio_fd, SNDCTL_DSP_SETTRIGGER, &value);
-	value = PCM_ENABLE_OUTPUT;
-	if ( ioctl(audio_fd, SNDCTL_DSP_SETTRIGGER, &value) < 0 ) {
-		SDL_SetError("Couldn't trigger audio output");
-		return(-1);
-	}
+    /* Trigger audio playback */
+    value = 0;
+    ioctl (audio_fd, SNDCTL_DSP_SETTRIGGER, &value);
+    value = PCM_ENABLE_OUTPUT;
+    if (ioctl (audio_fd, SNDCTL_DSP_SETTRIGGER, &value) < 0) {
+        SDL_SetError ("Couldn't trigger audio output");
+        return (-1);
+    }
 
-	/* Get the parent process id (we're the parent of the audio thread) */
-	parent = getpid();
+    /* Get the parent process id (we're the parent of the audio thread) */
+    parent = getpid ();
 
-	/* We're ready to rock and roll. :-) */
-	return(0);
+    /* We're ready to rock and roll. :-) */
+    return (0);
 }
+
+/* vi: set ts=4 sw=4 expandtab: */