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1 /*
2  *  Latency test program
3  *
4  *     Author: Jaroslav Kysela <perex@perex.cz>
5  *
6  *     Author of bandpass filter sweep effect:
7  *	       Maarten de Boer <mdeboer@iua.upf.es>
8  *
9  *  This small demo program can be used for measuring latency between
10  *  capture and playback. This latency is measured from driver (diff when
11  *  playback and capture was started). Scheduler is set to SCHED_RR.
12  *
13  *
14  *   This program is free software; you can redistribute it and/or modify
15  *   it under the terms of the GNU General Public License as published by
16  *   the Free Software Foundation; either version 2 of the License, or
17  *   (at your option) any later version.
18  *
19  *   This program is distributed in the hope that it will be useful,
20  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
21  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22  *   GNU General Public License for more details.
23  *
24  *   You should have received a copy of the GNU General Public License
25  *   along with this program; if not, write to the Free Software
26  *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
27  *
28  */
29 
30 #include "config.h"
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 #include <sched.h>
35 #include <errno.h>
36 #include <getopt.h>
37 #include <time.h>
38 #include "../include/asoundlib.h"
39 #include <sys/time.h>
40 #include <math.h>
41 
42 #ifndef CLOCK_MONOTONIC_RAW
43 #define CLOCK_MONOTONIC_RAW CLOCK_MONOTONIC
44 #endif
45 
46 #if defined(__OpenBSD__)
47 #define sched_getparam(pid, parm) (-1)
48 #define sched_setscheduler(pid, policy, parm) (-1)
49 #endif
50 
51 typedef struct timespec timestamp_t;
52 
53 char *sched_policy = "rr";
54 char *pdevice = "hw:0,0";
55 char *cdevice = "hw:0,0";
56 snd_pcm_format_t format = SND_PCM_FORMAT_S16_LE;
57 int rate = 22050;
58 int channels = 2;
59 int buffer_size = 0;		/* auto */
60 int period_size = 0;		/* auto */
61 int latency_min = 32;		/* in frames / 2 */
62 int latency_max = 2048;		/* in frames / 2 */
63 int loop_sec = 30;		/* seconds */
64 int block = 0;			/* block mode */
65 int use_poll = 0;
66 int usleep_val = 0;
67 int resample = 1;
68 int sys_latency = 0;		/* data I/O: use system timings instead driver wakeups */
69 int pos_dump = 0;		/* dump positions */
70 int realtime_check = 0;
71 unsigned long loop_limit;
72 snd_pcm_uframes_t playback_buffer_size;
73 
74 snd_output_t *output = NULL;
75 
frames_to_micro(size_t frames)76 static inline long long frames_to_micro(size_t frames)
77 {
78 	return (long long)((frames * 1000000LL) + (rate / 2)) / rate;
79 }
80 
timestamp_now(timestamp_t * tstamp)81 void timestamp_now(timestamp_t *tstamp)
82 {
83 	if (clock_gettime(CLOCK_MONOTONIC_RAW, tstamp))
84 		printf("clock_gettime() failed\n");
85 }
86 
timestamp_diff_micro(timestamp_t * tstamp)87 long long timestamp_diff_micro(timestamp_t *tstamp)
88 {
89 	timestamp_t now, diff;
90 	timestamp_now(&now);
91 	if (tstamp->tv_nsec > now.tv_nsec) {
92 		diff.tv_sec = now.tv_sec - tstamp->tv_sec - 1;
93 		diff.tv_nsec = (now.tv_nsec + 1000000000L) - tstamp->tv_nsec;
94 	} else {
95 		diff.tv_sec = now.tv_sec - tstamp->tv_sec;
96 		diff.tv_nsec = now.tv_nsec - tstamp->tv_nsec;
97 	}
98 	/* microseconds */
99 	return (diff.tv_sec * 1000000) + ((diff.tv_nsec + 500L) / 1000L);
100 }
101 
setparams_stream(snd_pcm_t * handle,snd_pcm_hw_params_t * params,const char * id)102 int setparams_stream(snd_pcm_t *handle,
103 		     snd_pcm_hw_params_t *params,
104 		     const char *id)
105 {
106 	int err;
107 	unsigned int rrate;
108 
109 	err = snd_pcm_hw_params_any(handle, params);
110 	if (err < 0) {
111 		printf("Broken configuration for %s PCM: no configurations available: %s\n", snd_strerror(err), id);
112 		return err;
113 	}
114 	err = snd_pcm_hw_params_set_rate_resample(handle, params, resample);
115 	if (err < 0) {
116 		printf("Resample setup failed for %s (val %i): %s\n", id, resample, snd_strerror(err));
117 		return err;
118 	}
119 	err = snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
120 	if (err < 0) {
121 		printf("Access type not available for %s: %s\n", id, snd_strerror(err));
122 		return err;
123 	}
124 	err = snd_pcm_hw_params_set_format(handle, params, format);
125 	if (err < 0) {
126 		printf("Sample format not available for %s: %s\n", id, snd_strerror(err));
127 		return err;
128 	}
129 	err = snd_pcm_hw_params_set_channels(handle, params, channels);
130 	if (err < 0) {
131 		printf("Channels count (%i) not available for %s: %s\n", channels, id, snd_strerror(err));
132 		return err;
133 	}
134 	rrate = rate;
135 	err = snd_pcm_hw_params_set_rate_near(handle, params, &rrate, 0);
136 	if (err < 0) {
137 		printf("Rate %iHz not available for %s: %s\n", rate, id, snd_strerror(err));
138 		return err;
139 	}
140 	if ((int)rrate != rate) {
141 		printf("Rate doesn't match (requested %iHz, get %iHz)\n", rate, err);
142 		return -EINVAL;
143 	}
144 	/* we do not want driver wakeups */
145 	if (sys_latency > 0 && snd_pcm_hw_params_can_disable_period_wakeup(params)) {
146 		err = snd_pcm_hw_params_set_period_wakeup(handle, params, 0);
147 		if (err < 0) {
148 			printf("Cannot disable period wakeups for %s\n", id);
149 			return err;
150 		}
151 	}
152 	return 0;
153 }
154 
setparams_bufsize(snd_pcm_t * handle,snd_pcm_hw_params_t * params,snd_pcm_hw_params_t * tparams,snd_pcm_uframes_t bufsize,const char * id)155 int setparams_bufsize(snd_pcm_t *handle,
156 		      snd_pcm_hw_params_t *params,
157 		      snd_pcm_hw_params_t *tparams,
158 		      snd_pcm_uframes_t bufsize,
159 		      const char *id)
160 {
161 	int err;
162 	snd_pcm_uframes_t periodsize;
163 
164 	snd_pcm_hw_params_copy(params, tparams);
165 	periodsize = bufsize * 2;
166 	err = snd_pcm_hw_params_set_buffer_size_near(handle, params, &periodsize);
167 	if (err < 0) {
168 		printf("Unable to set buffer size %li for %s: %s\n", bufsize * 2, id, snd_strerror(err));
169 		return err;
170 	}
171 	if (period_size > 0)
172 		periodsize = period_size;
173 	else
174 		periodsize /= 2;
175 	err = snd_pcm_hw_params_set_period_size_near(handle, params, &periodsize, 0);
176 	if (err < 0) {
177 		printf("Unable to set period size %li for %s: %s\n", periodsize, id, snd_strerror(err));
178 		return err;
179 	}
180 	return 0;
181 }
182 
setparams_set(snd_pcm_t * handle,snd_pcm_hw_params_t * params,snd_pcm_sw_params_t * swparams,const char * id)183 int setparams_set(snd_pcm_t *handle,
184 		  snd_pcm_hw_params_t *params,
185 		  snd_pcm_sw_params_t *swparams,
186 		  const char *id)
187 {
188 	int err;
189 	snd_pcm_uframes_t val;
190 
191 	err = snd_pcm_hw_params(handle, params);
192 	if (err < 0) {
193 		printf("Unable to set hw params for %s: %s\n", id, snd_strerror(err));
194 		return err;
195 	}
196 	err = snd_pcm_sw_params_current(handle, swparams);
197 	if (err < 0) {
198 		printf("Unable to determine current swparams for %s: %s\n", id, snd_strerror(err));
199 		return err;
200 	}
201 	err = snd_pcm_sw_params_set_start_threshold(handle, swparams, 0x7fffffff);
202 	if (err < 0) {
203 		printf("Unable to set start threshold mode for %s: %s\n", id, snd_strerror(err));
204 		return err;
205 	}
206 	if (!block)
207 		val = 4;
208 	else
209 		snd_pcm_hw_params_get_period_size(params, &val, NULL);
210 	err = snd_pcm_sw_params_set_avail_min(handle, swparams, val);
211 	if (err < 0) {
212 		printf("Unable to set avail min for %s: %s\n", id, snd_strerror(err));
213 		return err;
214 	}
215 	err = snd_pcm_sw_params(handle, swparams);
216 	if (err < 0) {
217 		printf("Unable to set sw params for %s: %s\n", id, snd_strerror(err));
218 		return err;
219 	}
220 	return 0;
221 }
222 
setparams(snd_pcm_t * phandle,snd_pcm_t * chandle,int * bufsize)223 int setparams(snd_pcm_t *phandle, snd_pcm_t *chandle, int *bufsize)
224 {
225 	int err, last_bufsize = *bufsize;
226 	snd_pcm_hw_params_t *pt_params, *ct_params;	/* templates with rate, format and channels */
227 	snd_pcm_hw_params_t *p_params, *c_params;
228 	snd_pcm_sw_params_t *p_swparams, *c_swparams;
229 	snd_pcm_uframes_t p_size, c_size, p_psize, c_psize;
230 	unsigned int p_time, c_time;
231 	unsigned int val;
232 
233 	snd_pcm_hw_params_alloca(&p_params);
234 	snd_pcm_hw_params_alloca(&c_params);
235 	snd_pcm_hw_params_alloca(&pt_params);
236 	snd_pcm_hw_params_alloca(&ct_params);
237 	snd_pcm_sw_params_alloca(&p_swparams);
238 	snd_pcm_sw_params_alloca(&c_swparams);
239 	if ((err = setparams_stream(phandle, pt_params, "playback")) < 0) {
240 		printf("Unable to set parameters for playback stream: %s\n", snd_strerror(err));
241 		exit(0);
242 	}
243 	if ((err = setparams_stream(chandle, ct_params, "capture")) < 0) {
244 		printf("Unable to set parameters for playback stream: %s\n", snd_strerror(err));
245 		exit(0);
246 	}
247 
248 	if (buffer_size > 0) {
249 		*bufsize = buffer_size;
250 		goto __set_it;
251 	}
252 
253       __again:
254       	if (buffer_size > 0)
255       		return -1;
256       	if (last_bufsize == *bufsize)
257 		*bufsize += 4;
258 	last_bufsize = *bufsize;
259 	if (*bufsize > latency_max)
260 		return -1;
261       __set_it:
262 	if ((err = setparams_bufsize(phandle, p_params, pt_params, *bufsize, "playback")) < 0) {
263 		printf("Unable to set hw parameters for playback stream: %s\n", snd_strerror(err));
264 		exit(0);
265 	}
266 	if ((err = setparams_bufsize(chandle, c_params, ct_params, *bufsize, "capture")) < 0) {
267 		printf("Unable to set hw parameters for capture stream: %s\n", snd_strerror(err));
268 		exit(0);
269 	}
270 
271 	snd_pcm_hw_params_get_period_size(p_params, &p_psize, NULL);
272 	if (p_psize > (unsigned int)*bufsize)
273 		*bufsize = p_psize;
274 	snd_pcm_hw_params_get_period_size(c_params, &c_psize, NULL);
275 	if (c_psize > (unsigned int)*bufsize)
276 		*bufsize = c_psize;
277 	snd_pcm_hw_params_get_period_time(p_params, &p_time, NULL);
278 	snd_pcm_hw_params_get_period_time(c_params, &c_time, NULL);
279 	if (p_time != c_time)
280 		goto __again;
281 
282 	snd_pcm_hw_params_get_buffer_size(p_params, &p_size);
283 	playback_buffer_size = p_size;
284 	if (p_psize * 2 < p_size) {
285                 snd_pcm_hw_params_get_periods_min(p_params, &val, NULL);
286                 if (val > 2) {
287 			printf("playback device does not support 2 periods per buffer\n");
288 			exit(0);
289 		}
290 		goto __again;
291 	}
292 	snd_pcm_hw_params_get_buffer_size(c_params, &c_size);
293 	if (c_psize * 2 < c_size) {
294                 snd_pcm_hw_params_get_periods_min(c_params, &val, NULL);
295 		if (val > 2 ) {
296 			printf("capture device does not support 2 periods per buffer\n");
297 			exit(0);
298 		}
299 		goto __again;
300 	}
301 	if ((err = setparams_set(phandle, p_params, p_swparams, "playback")) < 0) {
302 		printf("Unable to set sw parameters for playback stream: %s\n", snd_strerror(err));
303 		exit(0);
304 	}
305 	if ((err = setparams_set(chandle, c_params, c_swparams, "capture")) < 0) {
306 		printf("Unable to set sw parameters for playback stream: %s\n", snd_strerror(err));
307 		exit(0);
308 	}
309 
310 	if ((err = snd_pcm_prepare(phandle)) < 0) {
311 		printf("Prepare error: %s\n", snd_strerror(err));
312 		exit(0);
313 	}
314 
315 	snd_pcm_dump(phandle, output);
316 	snd_pcm_dump(chandle, output);
317 	fflush(stdout);
318 	return 0;
319 }
320 
showstat(snd_pcm_t * handle,size_t frames)321 void showstat(snd_pcm_t *handle, size_t frames)
322 {
323 	int err;
324 	snd_pcm_status_t *status;
325 
326 	snd_pcm_status_alloca(&status);
327 	if ((err = snd_pcm_status(handle, status)) < 0) {
328 		printf("Stream status error: %s\n", snd_strerror(err));
329 		exit(0);
330 	}
331 	printf("*** frames = %li ***\n", (long)frames);
332 	snd_pcm_status_dump(status, output);
333 }
334 
showlatency(size_t latency)335 void showlatency(size_t latency)
336 {
337 	double d;
338 	latency *= 2;
339 	d = (double)latency / (double)rate;
340 	printf("Trying latency %li frames, %.3fus, %.6fms (%.4fHz)\n", (long)latency, d * 1000000, d * 1000, (double)1 / d);
341 }
342 
showinmax(size_t in_max)343 void showinmax(size_t in_max)
344 {
345 	double d;
346 
347 	printf("Maximum read: %li frames\n", (long)in_max);
348 	d = (double)in_max / (double)rate;
349 	printf("Maximum read latency: %.3fus, %.6fms (%.4fHz)\n", d * 1000000, d * 1000, (double)1 / d);
350 }
351 
gettimestamp(snd_pcm_t * handle,snd_timestamp_t * timestamp)352 void gettimestamp(snd_pcm_t *handle, snd_timestamp_t *timestamp)
353 {
354 	int err;
355 	snd_pcm_status_t *status;
356 
357 	snd_pcm_status_alloca(&status);
358 	if ((err = snd_pcm_status(handle, status)) < 0) {
359 		printf("Stream status error: %s\n", snd_strerror(err));
360 		exit(0);
361 	}
362 	snd_pcm_status_get_trigger_tstamp(status, timestamp);
363 }
364 
setscheduler(void)365 void setscheduler(void)
366 {
367 	struct sched_param sched_param;
368 	int policy = SCHED_RR;
369 	const char *spolicy = "Round Robin";
370 
371 	if (strcasecmp(sched_policy, "fifo") == 0) {
372 		policy = SCHED_FIFO;
373 		spolicy = "FIFO";
374 	} else if (strcasecmp(sched_policy, "other") == 0) {
375 		policy = SCHED_OTHER;
376 		spolicy = "OTHER";
377 	}
378 	if (sched_getparam(0, &sched_param) < 0) {
379 		printf("Scheduler getparam failed...\n");
380 		return;
381 	}
382 	sched_param.sched_priority = sched_get_priority_max(policy);
383 	if (!sched_setscheduler(0, policy, &sched_param)) {
384 		printf("Scheduler set to %s with priority %i...\n", spolicy, sched_param.sched_priority);
385 		fflush(stdout);
386 		return;
387 	}
388 	printf("!!!Scheduler set to %s with priority %i FAILED!!!\n", spolicy, sched_param.sched_priority);
389 }
390 
timediff(snd_timestamp_t t1,snd_timestamp_t t2)391 long timediff(snd_timestamp_t t1, snd_timestamp_t t2)
392 {
393 	signed long l;
394 
395 	t1.tv_sec -= t2.tv_sec;
396 	l = (signed long) t1.tv_usec - (signed long) t2.tv_usec;
397 	if (l < 0) {
398 		t1.tv_sec--;
399 		l = 1000000 + l;
400 		l %= 1000000;
401 	}
402 	return (t1.tv_sec * 1000000) + l;
403 }
404 
readbuf(snd_pcm_t * handle,char * buf,long len,size_t * frames,size_t * max)405 long readbuf(snd_pcm_t *handle, char *buf, long len, size_t *frames, size_t *max)
406 {
407 	long r;
408 
409 	if (!block) {
410 		do {
411 			r = snd_pcm_readi(handle, buf, len);
412 		} while (r == -EAGAIN);
413 		if (r > 0) {
414 			*frames += r;
415 			if ((long)*max < r)
416 				*max = r;
417 		}
418 		// printf("read = %li\n", r);
419 	} else {
420 		int frame_bytes = (snd_pcm_format_physical_width(format) / 8) * channels;
421 		do {
422 			r = snd_pcm_readi(handle, buf, len);
423 			if (r > 0) {
424 				buf += r * frame_bytes;
425 				len -= r;
426 				*frames += r;
427 				if ((long)*max < r)
428 					*max = r;
429 			}
430 			// printf("r = %li, len = %li\n", r, len);
431 		} while (r >= 1 && len > 0);
432 	}
433 	// showstat(handle, 0);
434 	return r;
435 }
436 
writebuf(snd_pcm_t * handle,char * buf,long len,size_t * frames)437 long writebuf(snd_pcm_t *handle, char *buf, long len, size_t *frames)
438 {
439 	long r;
440 	int frame_bytes = (snd_pcm_format_physical_width(format) / 8) * channels;
441 
442 	while (len > 0) {
443 		r = snd_pcm_writei(handle, buf, len);
444 		if (r == -EAGAIN)
445 			continue;
446 		// printf("write = %li\n", r);
447 		if (r < 0)
448 			return r;
449 		// showstat(handle, 0);
450 		buf += r * frame_bytes;
451 		len -= r;
452 		*frames += r;
453 	}
454 	return 0;
455 }
456 
457 #define FILTERSWEEP_LFO_CENTER 2000.
458 #define FILTERSWEEP_LFO_DEPTH 1800.
459 #define FILTERSWEEP_LFO_FREQ 0.2
460 #define FILTER_BANDWIDTH 50
461 
462 /* filter the sweep variables */
463 float lfo,dlfo,fs,fc,BW,C,D,a0,a1,a2,b1,b2,*x[3],*y[3];
464 
applyeffect(char * buffer,int r)465 void applyeffect(char* buffer,int r)
466 {
467 	short* samples = (short*) buffer;
468 	int i;
469 	for (i=0;i<r;i++)
470 	{
471 		int chn;
472 
473 		fc = sin(lfo)*FILTERSWEEP_LFO_DEPTH+FILTERSWEEP_LFO_CENTER;
474 		lfo += dlfo;
475 		if (lfo>2.*M_PI) lfo -= 2.*M_PI;
476 		C = 1./tan(M_PI*BW/fs);
477 		D = 2.*cos(2*M_PI*fc/fs);
478 		a0 = 1./(1.+C);
479 		a1 = 0;
480 		a2 = -a0;
481 		b1 = -C*D*a0;
482 		b2 = (C-1)*a0;
483 
484 		for (chn=0;chn<channels;chn++)
485 		{
486 			x[chn][2] = x[chn][1];
487 			x[chn][1] = x[chn][0];
488 
489 			y[chn][2] = y[chn][1];
490 			y[chn][1] = y[chn][0];
491 
492 			x[chn][0] = samples[i*channels+chn];
493 			y[chn][0] = a0*x[chn][0] + a1*x[chn][1] + a2*x[chn][2]
494 				- b1*y[chn][1] - b2*y[chn][2];
495 			samples[i*channels+chn] = y[chn][0];
496 		}
497 	}
498 }
499 
get_avail(snd_pcm_t * pcm)500 static ssize_t get_avail(snd_pcm_t *pcm)
501 {
502 	ssize_t avail;
503 
504 	while (1) {
505 		avail = snd_pcm_avail(pcm);
506 		if (avail == -EAGAIN)
507 			continue;
508 		break;
509 	}
510 	return avail;
511 }
512 
help(void)513 void help(void)
514 {
515 	int k;
516 	printf(
517 "Usage: latency [OPTION]... [FILE]...\n"
518 "-h,--help      help\n"
519 "-P,--pdevice   playback device\n"
520 "-C,--cdevice   capture device\n"
521 "-m,--min       minimum latency in frames\n"
522 "-M,--max       maximum latency in frames\n"
523 "-U,--updates   I/O updates in milliseconds (0 = off)\n"
524 "-F,--frames    frames to transfer\n"
525 "-f,--format    sample format\n"
526 "-c,--channels  channels\n"
527 "-r,--rate      rate\n"
528 "-B,--buffer    buffer size in frames\n"
529 "-E,--period    period size in frames\n"
530 "-s,--seconds   duration of test in seconds\n"
531 "-b,--block     block mode\n"
532 "-p,--poll      use poll (wait for event - reduces CPU usage)\n"
533 "-y,--usleep    sleep for the specified amount of microseconds between\n"
534 "               stream updates (default 0 - off)\n"
535 "-e,--effect    apply an effect (bandpass filter sweep)\n"
536 "-x,--posdump   dump buffer positions\n"
537 "-X,--realtime  do a realtime check (buffering)\n"
538 "-O,--policy    set scheduler policy (RR, FIFO or OTHER)\n"
539 );
540         printf("Recognized sample formats are:");
541         for (k = 0; k < SND_PCM_FORMAT_LAST; ++k) {
542                 const char *s = snd_pcm_format_name(k);
543                 if (s)
544                         printf(" %s", s);
545         }
546         printf("\n\n");
547         printf(
548 "Tip #1 (usable latency with large periods, non-blocking mode, good CPU usage,\n"
549 "        superb xrun prevention):\n"
550 "  latency -m 8192 -M 8192 -t 1 -p\n"
551 "Tip #2 (superb latency, non-blocking mode, but heavy CPU usage):\n"
552 "  latency -m 128 -M 128\n"
553 );
554 }
555 
main(int argc,char * argv[])556 int main(int argc, char *argv[])
557 {
558 	struct option long_option[] =
559 	{
560 		{"help", 0, NULL, 'h'},
561 		{"pdevice", 1, NULL, 'P'},
562 		{"cdevice", 1, NULL, 'C'},
563 		{"min", 1, NULL, 'm'},
564 		{"max", 1, NULL, 'M'},
565 		{"updates", 1, NULL, 'U'},
566 		{"frames", 1, NULL, 'F'},
567 		{"format", 1, NULL, 'f'},
568 		{"channels", 1, NULL, 'c'},
569 		{"rate", 1, NULL, 'r'},
570 		{"buffer", 1, NULL, 'B'},
571 		{"period", 1, NULL, 'E'},
572 		{"seconds", 1, NULL, 's'},
573 		{"block", 0, NULL, 'b'},
574 		{"poll", 0, NULL, 'p'},
575 		{"usleep", 1, NULL, 'y'},
576 		{"effect", 0, NULL, 'e'},
577 		{"posdump", 0, NULL, 'x'},
578 		{"realtime", 0, NULL, 'X'},
579 		{"policy", 1, NULL, 'O'},
580 		{NULL, 0, NULL, 0},
581 	};
582 	snd_pcm_t *phandle, *chandle;
583 	char *buffer;
584 	int err, latency, morehelp;
585 	int ok;
586 	snd_timestamp_t p_tstamp, c_tstamp;
587 	ssize_t r, cap_avail, cap_avail_max, pbk_fill, pbk_fill_min;
588 	size_t frames_in, frames_out, in_max;
589 	timestamp_t tstamp_start;
590 	int effect = 0;
591 	morehelp = 0;
592 	while (1) {
593 		int c;
594 		if ((c = getopt_long(argc, argv, "hP:C:m:M:U:F:f:c:r:B:E:s:y:O:bpenxX", long_option, NULL)) < 0)
595 			break;
596 		switch (c) {
597 		case 'h':
598 			morehelp++;
599 			break;
600 		case 'P':
601 			pdevice = strdup(optarg);
602 			break;
603 		case 'C':
604 			cdevice = strdup(optarg);
605 			break;
606 		case 'm':
607 			err = atoi(optarg) / 2;
608 			latency_min = err >= 4 ? err : 4;
609 			if (latency_max < latency_min)
610 				latency_max = latency_min;
611 			break;
612 		case 'M':
613 			err = atoi(optarg) / 2;
614 			latency_max = latency_min > err ? latency_min : err;
615 			break;
616 		case 'U':
617 			err = atoi(optarg);
618 			sys_latency = err <= 0 ? 0 : err;
619 			break;
620 		case 'f':
621 			format = snd_pcm_format_value(optarg);
622 			if (format == SND_PCM_FORMAT_UNKNOWN) {
623 				printf("Unknown format, setting to default S16_LE\n");
624 				format = SND_PCM_FORMAT_S16_LE;
625 			}
626 			break;
627 		case 'c':
628 			err = atoi(optarg);
629 			channels = err >= 1 && err < 1024 ? err : 1;
630 			break;
631 		case 'r':
632 			err = atoi(optarg);
633 			rate = err >= 4000 && err < 200000 ? err : 44100;
634 			break;
635 		case 'B':
636 			err = atoi(optarg);
637 			buffer_size = err >= 32 && err < 200000 ? err : 0;
638 			break;
639 		case 'E':
640 			err = atoi(optarg);
641 			period_size = err >= 32 && err < 200000 ? err : 0;
642 			break;
643 		case 's':
644 			err = atoi(optarg);
645 			loop_sec = err >= 1 && err <= 100000 ? err : 30;
646 			break;
647 		case 'b':
648 			block = 1;
649 			break;
650 		case 'p':
651 			use_poll = 1;
652 			break;
653 		case 'y':
654 			usleep_val = atoi(optarg);
655 			break;
656 		case 'e':
657 			effect = 1;
658 			break;
659 		case 'n':
660 			resample = 0;
661 			break;
662 		case 'x':
663 			pos_dump = 1;
664 			break;
665 		case 'X':
666 			realtime_check = 1;
667 			break;
668 		case 'O':
669 			sched_policy = optarg;
670 			break;
671 		}
672 	}
673 
674 	if (morehelp) {
675 		help();
676 		return 0;
677 	}
678 	err = snd_output_stdio_attach(&output, stdout, 0);
679 	if (err < 0) {
680 		printf("Output failed: %s\n", snd_strerror(err));
681 		return 0;
682 	}
683 
684 	loop_limit = loop_sec * rate;
685 	latency = latency_min - 4;
686 	buffer = malloc((latency_max * 2 * snd_pcm_format_physical_width(format) / 8) * channels);
687 
688 	/* I/O updates based on a system timer */
689 	if (sys_latency > 0) {
690 		block = 0;
691 		use_poll = 0;
692 	}
693 
694 	setscheduler();
695 
696 	printf("Playback device is %s\n", pdevice);
697 	printf("Capture device is %s\n", cdevice);
698 	printf("Parameters are %iHz, %s, %i channels, %s mode, use poll %s\n",
699 			rate, snd_pcm_format_name(format),
700 			channels, block ? "blocking" : "non-blocking",
701 			use_poll ? "yes" : "no");
702 	printf("Loop limit is %lu frames, minimum latency = %i, maximum latency = %i",
703 			loop_limit, latency_min * 2, latency_max * 2);
704 	if (sys_latency > 0)
705 		printf(", I/O updates %ims", sys_latency);
706 	else if (!block && !use_poll)
707 		printf(", I/O usleep %ius", usleep_val);
708 	printf("\n");
709 
710 	if ((err = snd_pcm_open(&phandle, pdevice, SND_PCM_STREAM_PLAYBACK, block ? 0 : SND_PCM_NONBLOCK)) < 0) {
711 		printf("Playback open error: %s\n", snd_strerror(err));
712 		return 0;
713 	}
714 	if ((err = snd_pcm_open(&chandle, cdevice, SND_PCM_STREAM_CAPTURE, block ? 0 : SND_PCM_NONBLOCK)) < 0) {
715 		printf("Record open error: %s\n", snd_strerror(err));
716 		return 0;
717 	}
718 
719 	/* initialize the filter sweep variables */
720 	if (effect) {
721 		fs = (float) rate;
722 		BW = FILTER_BANDWIDTH;
723 
724 		lfo = 0;
725 		dlfo = 2.*M_PI*FILTERSWEEP_LFO_FREQ/fs;
726 
727 		x[0] = (float*) malloc(channels*sizeof(float));
728 		x[1] = (float*) malloc(channels*sizeof(float));
729 		x[2] = (float*) malloc(channels*sizeof(float));
730 		y[0] = (float*) malloc(channels*sizeof(float));
731 		y[1] = (float*) malloc(channels*sizeof(float));
732 		y[2] = (float*) malloc(channels*sizeof(float));
733 	}
734 
735 	cap_avail_max = 0;
736 	pbk_fill_min = latency * 2;
737 
738 	while (1) {
739 		frames_in = frames_out = 0;
740 		if (setparams(phandle, chandle, &latency) < 0)
741 			break;
742 		showlatency(latency);
743 		if ((err = snd_pcm_link(chandle, phandle)) < 0) {
744 			printf("Streams link error: %s\n", snd_strerror(err));
745 			exit(0);
746 		}
747 		if (snd_pcm_format_set_silence(format, buffer, latency * channels) < 0) {
748 			fprintf(stderr, "silence error\n");
749 			break;
750 		}
751 		if (writebuf(phandle, buffer, latency, &frames_out) < 0) {
752 			fprintf(stderr, "write error\n");
753 			break;
754 		}
755 		if (writebuf(phandle, buffer, latency, &frames_out) < 0) {
756 			fprintf(stderr, "write error\n");
757 			break;
758 		}
759 
760 		if (realtime_check)
761 			timestamp_now(&tstamp_start);
762 		if ((err = snd_pcm_start(chandle)) < 0) {
763 			printf("Go error: %s\n", snd_strerror(err));
764 			exit(0);
765 		}
766 		if (realtime_check)
767 			printf("[%lldus] Stream start\n", timestamp_diff_micro(&tstamp_start));
768 		gettimestamp(phandle, &p_tstamp);
769 		gettimestamp(chandle, &c_tstamp);
770 #if 0
771 		printf("Playback:\n");
772 		showstat(phandle, frames_out);
773 		printf("Capture:\n");
774 		showstat(chandle, frames_in);
775 #endif
776 
777 		ok = 1;
778 		in_max = 0;
779 		while (ok && frames_in < loop_limit) {
780 			cap_avail = latency;
781 			if (sys_latency > 0) {
782 				poll(NULL, 0, sys_latency);
783 				cap_avail = get_avail(chandle);
784 				if (cap_avail < 0) {
785 					printf("Avail failed: %s\n", snd_strerror(cap_avail));
786 					ok = 0;
787 					break;
788 				}
789 			} else if (use_poll) {
790 				/* use poll to wait for next event */
791 				snd_pcm_wait(chandle, 1000);
792 			} else if (!block && usleep_val > 0) {
793 				usleep(usleep_val);
794 			}
795 			if (pos_dump || realtime_check) {
796 				if (sys_latency <= 0)
797 					cap_avail = get_avail(chandle);
798 				pbk_fill = get_avail(phandle);
799 				if (pbk_fill >= 0)
800 					pbk_fill = playback_buffer_size - pbk_fill;
801 				if (cap_avail > cap_avail_max)
802 					cap_avail_max = cap_avail;
803 				if (pbk_fill >= 0 && pbk_fill < pbk_fill_min)
804 					pbk_fill_min = pbk_fill;
805 				if (realtime_check) {
806 					long long diff = timestamp_diff_micro(&tstamp_start);
807 					long long cap_pos = frames_to_micro(frames_in + cap_avail);
808 					long long pbk_pos = frames_to_micro(frames_out - pbk_fill);
809 					printf("[%lldus] POS: p=%zd (min=%zd, rt=%lldus) c=%zd (max=%zd, rt=%lldus)\n",
810 							diff, pbk_fill, pbk_fill_min, pbk_pos - diff,
811 							cap_avail, cap_avail_max, cap_pos - diff);
812 				} else if (pos_dump) {
813 					printf("POS: p=%zd (min=%zd), c=%zd (max=%zd)\n",
814 							pbk_fill, pbk_fill_min, cap_avail, cap_avail_max);
815 				}
816 			}
817 			if ((r = readbuf(chandle, buffer, cap_avail, &frames_in, &in_max)) < 0)
818 				ok = 0;
819 			else {
820 				if (effect)
821 					applyeffect(buffer, r);
822 			 	if (writebuf(phandle, buffer, r, &frames_out) < 0)
823 					ok = 0;
824 			}
825 		}
826 		if (ok)
827 			printf("Success\n");
828 		else
829 			printf("Failure\n");
830 		printf("Playback:\n");
831 		showstat(phandle, frames_out);
832 		printf("Capture:\n");
833 		showstat(chandle, frames_in);
834 		showinmax(in_max);
835 		if (p_tstamp.tv_sec == c_tstamp.tv_sec &&
836 		    p_tstamp.tv_usec == c_tstamp.tv_usec)
837 			printf("Hardware sync\n");
838 		if (realtime_check) {
839 			long long diff = timestamp_diff_micro(&tstamp_start);
840 			long long mtime = frames_to_micro(frames_in);
841 			printf("Elapsed real time: %lldus\n", diff);
842 			printf("Elapsed device time: %lldus\n", mtime);
843 			printf("Test time diff (device - real): %lldus\n", mtime - diff);
844 		}
845 		snd_pcm_drop(chandle);
846 		snd_pcm_nonblock(phandle, 0);
847 		snd_pcm_drain(phandle);
848 		snd_pcm_nonblock(phandle, !block ? 1 : 0);
849 		if (ok) {
850 #if 1
851 			printf("Playback time = %li.%i, Record time = %li.%i, diff = %li\n",
852 			       (long)p_tstamp.tv_sec,
853 			       (int)p_tstamp.tv_usec,
854 			       (long)c_tstamp.tv_sec,
855 			       (int)c_tstamp.tv_usec,
856 			       timediff(p_tstamp, c_tstamp));
857 #endif
858 			break;
859 		}
860 		snd_pcm_unlink(chandle);
861 		snd_pcm_hw_free(phandle);
862 		snd_pcm_hw_free(chandle);
863 	}
864 	snd_pcm_close(phandle);
865 	snd_pcm_close(chandle);
866 	snd_output_close(output);
867 	snd_config_update_free_global();
868 	free(buffer);
869 	free(pdevice);
870 	free(cdevice);
871 	return 0;
872 }
873