Fixed bug 4642 - Rework SDL_netbsdaudio to improve performance Nia Alarie The NetBSD audio driver has a few problems. Lots of obsolete code, and extremely bad performance and stuttering. I have a patch in NetBSD's package system to improve it. This is my attempt to upstream it. The changes include: * Removing references to defines which are never used. * Using the correct structures for playback and recording, previously they were the wrong way around. * Using the correct types ('struct audio_prinfo' in contrast to 'audio_prinfo') * Removing the use of non-blocking I/O, as suggested in #3177. * Removing workarounds for driver bugs on systems that don't exist or use this driver any more. * Removing all usage of SDL_Delay(1) * Removing pointless use of AUDIO_INITINFO and tests that expect AUDIO_SETINFO to fail when it can't. These changes bring its performance in line with the DSP audio driver.
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diff --git a/src/audio/netbsd/SDL_netbsdaudio.c b/src/audio/netbsd/SDL_netbsdaudio.c
index 5b50d52..bfdbfc4 100644
--- a/src/audio/netbsd/SDL_netbsdaudio.c
+++ b/src/audio/netbsd/SDL_netbsdaudio.c
@@ -43,12 +43,7 @@
#include "../SDL_audiodev_c.h"
#include "SDL_netbsdaudio.h"
-/* Use timer for synchronization */
-/* #define USE_TIMER_SYNC */
-
/* #define DEBUG_AUDIO */
-/* #define DEBUG_AUDIO_STREAM */
-
static void
NETBSDAUDIO_DetectDevices(void)
@@ -63,14 +58,14 @@ NETBSDAUDIO_Status(_THIS)
#ifdef DEBUG_AUDIO
/* *INDENT-OFF* */
audio_info_t info;
- const audio_prinfo *prinfo;
+ const struct audio_prinfo *prinfo;
if (ioctl(this->hidden->audio_fd, AUDIO_GETINFO, &info) < 0) {
fprintf(stderr, "AUDIO_GETINFO failed.\n");
return;
}
- prinfo = this->iscapture ? &info.play : &info.record;
+ prinfo = this->iscapture ? &info.record : &info.play;
fprintf(stderr, "\n"
"[%s info]\n"
@@ -115,90 +110,37 @@ NETBSDAUDIO_Status(_THIS)
(info.mode == AUMODE_PLAY) ? "PLAY"
: (info.mode = AUMODE_RECORD) ? "RECORD"
: (info.mode == AUMODE_PLAY_ALL ? "PLAY_ALL" : "?"));
+
+ fprintf(stderr, "\n"
+ "[audio spec]\n"
+ "format : 0x%x\n"
+ "size : %u\n"
+ "",
+ this->spec.format,
+ this->spec.size);
/* *INDENT-ON* */
#endif /* DEBUG_AUDIO */
}
-/* This function waits until it is possible to write a full sound buffer */
-static void
-NETBSDAUDIO_WaitDevice(_THIS)
-{
-#ifndef USE_BLOCKING_WRITES /* Not necessary when using blocking writes */
- /* See if we need to use timed audio synchronization */
- if (this->hidden->frame_ticks) {
- /* Use timer for general audio synchronization */
- Sint32 ticks;
-
- ticks = ((Sint32) (this->hidden->next_frame - SDL_GetTicks())) - FUDGE_TICKS;
- if (ticks > 0) {
- SDL_Delay(ticks);
- }
- } else {
- /* Use SDL_IOReady() for audio synchronization */
-#ifdef DEBUG_AUDIO
- fprintf(stderr, "Waiting for audio to get ready\n");
-#endif
- if (SDL_IOReady(this->hidden->audio_fd, SDL_TRUE, 10 * 1000)
- <= 0) {
- const char *message =
- "Audio timeout - buggy audio driver? (disabled)";
- /* 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);
- SDL_OpenedAudioDeviceDisconnected(this);
- /* Don't try to close - may hang */
- this->hidden->audio_fd = -1;
-#ifdef DEBUG_AUDIO
- fprintf(stderr, "Done disabling audio\n");
-#endif
- }
-#ifdef DEBUG_AUDIO
- fprintf(stderr, "Ready!\n");
-#endif
- }
-#endif /* !USE_BLOCKING_WRITES */
-}
-
static void
NETBSDAUDIO_PlayDevice(_THIS)
{
- int written, p = 0;
-
- /* Write the audio data, checking for EAGAIN on broken audio drivers */
- do {
- written = write(this->hidden->audio_fd,
- &this->hidden->mixbuf[p], this->hidden->mixlen - p);
-
- if (written > 0)
- p += written;
- if (written == -1 && errno != 0 && errno != EAGAIN && errno != EINTR) {
- /* Non recoverable error has occurred. It should be reported!!! */
- perror("audio");
- break;
- }
-
-#ifdef DEBUG_AUDIO
- fprintf(stderr, "Wrote %d bytes of audio data\n", written);
-#endif
-
- if (p < this->hidden->mixlen
- || ((written < 0) && ((errno == 0) || (errno == EAGAIN)))) {
- SDL_Delay(1); /* Let a little CPU time go by */
- }
- } while (p < this->hidden->mixlen);
-
- /* If timer synchronization is enabled, set the next write frame */
- if (this->hidden->frame_ticks) {
- this->hidden->next_frame += this->hidden->frame_ticks;
- }
+ struct SDL_PrivateAudioData *h = this->hidden;
+ int written;
- /* If we couldn't write, assume fatal error for now */
- if (written < 0) {
+ /* Write the audio data */
+ written = write(h->audio_fd, h->mixbuf, h->mixlen);
+ if (written == -1) {
+ /* Non recoverable error has occurred. It should be reported!!! */
SDL_OpenedAudioDeviceDisconnected(this);
+ perror("audio");
+ return;
}
+
+#ifdef DEBUG_AUDIO
+ fprintf(stderr, "Wrote %d bytes of audio data\n", written);
+#endif
}
static Uint8 *
@@ -212,28 +154,19 @@ static int
NETBSDAUDIO_CaptureFromDevice(_THIS, void *_buffer, int buflen)
{
Uint8 *buffer = (Uint8 *) _buffer;
- int br, p = 0;
-
- /* Capture the audio data, checking for EAGAIN on broken audio drivers */
- do {
- br = read(this->hidden->audio_fd, buffer + p, buflen - p);
- if (br > 0)
- p += br;
- if (br == -1 && errno != 0 && errno != EAGAIN && errno != EINTR) {
- /* Non recoverable error has occurred. It should be reported!!! */
- perror("audio");
- return p ? p : -1;
- }
+ int br;
+
+ br = read(this->hidden->audio_fd, buffer, buflen);
+ if (br == -1) {
+ /* Non recoverable error has occurred. It should be reported!!! */
+ perror("audio");
+ return -1;
+ }
#ifdef DEBUG_AUDIO
- fprintf(stderr, "Captured %d bytes of audio data\n", br);
+ fprintf(stderr, "Captured %d bytes of audio data\n", br);
#endif
-
- if (p < buflen
- || ((br < 0) && ((errno == 0) || (errno == EAGAIN)))) {
- SDL_Delay(1); /* Let a little CPU time go by */
- }
- } while (p < buflen);
+ return 0;
}
static void
@@ -271,10 +204,9 @@ NETBSDAUDIO_CloseDevice(_THIS)
static int
NETBSDAUDIO_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
{
- const int flags = iscapture ? OPEN_FLAGS_INPUT : OPEN_FLAGS_OUTPUT;
SDL_AudioFormat format = 0;
audio_info_t info;
- audio_prinfo *prinfo = iscapture ? &info.play : &info.record;
+ struct audio_prinfo *prinfo = iscapture ? &info.record : &info.play;
/* We don't care what the devname is...we'll try to open anything. */
/* ...but default to first name in the list... */
@@ -294,25 +226,16 @@ NETBSDAUDIO_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
SDL_zerop(this->hidden);
/* Open the audio device */
- this->hidden->audio_fd = open(devname, flags, 0);
+ this->hidden->audio_fd = open(devname, iscapture ? O_RDONLY : O_WRONLY);
if (this->hidden->audio_fd < 0) {
return SDL_SetError("Couldn't open %s: %s", devname, strerror(errno));
}
AUDIO_INITINFO(&info);
- /* Calculate the final parameters for this audio specification */
- SDL_CalculateAudioSpec(&this->spec);
-
- /* Set to play mode */
- info.mode = iscapture ? AUMODE_RECORD : AUMODE_PLAY;
- if (ioctl(this->hidden->audio_fd, AUDIO_SETINFO, &info) < 0) {
- return SDL_SetError("Couldn't put device into play mode");
- }
+ prinfo->encoding = AUDIO_ENCODING_NONE;
- AUDIO_INITINFO(&info);
- for (format = SDL_FirstAudioFormat(this->spec.format);
- format; format = SDL_NextAudioFormat()) {
+ for (format = SDL_FirstAudioFormat(this->spec.format); format;) {
switch (format) {
case AUDIO_U8:
prinfo->encoding = AUDIO_ENCODING_ULINEAR;
@@ -338,34 +261,33 @@ NETBSDAUDIO_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
prinfo->encoding = AUDIO_ENCODING_ULINEAR_BE;
prinfo->precision = 16;
break;
- default:
- continue;
}
-
- if (ioctl(this->hidden->audio_fd, AUDIO_SETINFO, &info) == 0) {
+ if (prinfo->encoding != AUDIO_ENCODING_NONE) {
break;
}
+ format = SDL_NextAudioFormat();
}
- if (!format) {
+ if (prinfo->encoding == AUDIO_ENCODING_NONE) {
return SDL_SetError("No supported encoding for 0x%x", this->spec.format);
}
this->spec.format = format;
- AUDIO_INITINFO(&info);
- prinfo->channels = this->spec.channels;
- if (ioctl(this->hidden->audio_fd, AUDIO_SETINFO, &info) == -1) {
- this->spec.channels = 1;
- }
- AUDIO_INITINFO(&info);
- prinfo->sample_rate = this->spec.freq;
+ /* Calculate spec parameters based on our chosen format */
+ SDL_CalculateAudioSpec(&this->spec);
+
+ info.mode = iscapture ? AUMODE_RECORD : AUMODE_PLAY;
info.blocksize = this->spec.size;
info.hiwat = 5;
info.lowat = 3;
+ prinfo->sample_rate = this->spec.freq;
+ prinfo->channels = this->spec.channels;
(void) ioctl(this->hidden->audio_fd, AUDIO_SETINFO, &info);
+
(void) ioctl(this->hidden->audio_fd, AUDIO_GETINFO, &info);
this->spec.freq = prinfo->sample_rate;
+ this->spec.channels = prinfo->channels;
if (!iscapture) {
/* Allocate mixing buffer */
@@ -390,7 +312,6 @@ NETBSDAUDIO_Init(SDL_AudioDriverImpl * impl)
impl->DetectDevices = NETBSDAUDIO_DetectDevices;
impl->OpenDevice = NETBSDAUDIO_OpenDevice;
impl->PlayDevice = NETBSDAUDIO_PlayDevice;
- impl->WaitDevice = NETBSDAUDIO_WaitDevice;
impl->GetDeviceBuf = NETBSDAUDIO_GetDeviceBuf;
impl->CloseDevice = NETBSDAUDIO_CloseDevice;
impl->CaptureFromDevice = NETBSDAUDIO_CaptureFromDevice;