pcm core: fixed spurious XRUN issues

This fixes the numerous XRUN issues seen on some cards.
The trick is to set the buffer_size & period size in
hw parameters. These ones are calculated from an expected
maximum latency.
Also, the writei is done in a loop to be robust to overruns
and partial writes.

Signed-off-by: Thierry Bultel <thierry.bultel@iot.bzh>

2 files changed, 257 insertions, 95 deletions

diff --git a/plugins/alsa/alsa-core-pcm.c b/plugins/alsa/alsa-core-pcm.c
index aed5f22..7cec020 100644
--- a/plugins/alsa/alsa-core-pcm.c
+++ b/plugins/alsa/alsa-core-pcm.c
@@ -29,6 +29,9 @@ for the specific language governing permissions and
 #include <sys/syscall.h>
 #include <sched.h>
 
+static int xrun(snd_pcm_t * pcm);
+static int suspend(snd_pcm_t * pcm);
+
 STATIC int AlsaPeriodSize(snd_pcm_format_t pcmFormat) {
     int pcmSampleSize;
 
@@ -60,29 +63,46 @@ STATIC int AlsaPeriodSize(snd_pcm_format_t pcmFormat) {
     return pcmSampleSize;
 }
 
-PUBLIC int AlsaPcmConf(SoftMixerT *mixer, AlsaPcmCtlT *pcm, AlsaPcmHwInfoT *opts) {
+PUBLIC int AlsaPcmConf(SoftMixerT *mixer, AlsaPcmCtlT *pcm, AlsaPcmHwInfoT *opts, int mode) {
     int error;
     snd_pcm_hw_params_t *pxmHwParams;
     snd_pcm_sw_params_t *pxmSwParams;
     snd_pcm_format_t format;
     snd_pcm_access_t access;
 
+    AFB_ApiInfo(mixer->api,
+                "%s: mixer info %s uid %s , pcm %s, mode %d",
+                __func__, mixer->info, mixer->uid, pcm->cid.cardid, mode);
+
     // retrieve hardware config from PCM
     snd_pcm_hw_params_alloca(&pxmHwParams);
-    snd_pcm_hw_params_any(pcm->handle, pxmHwParams);
+    error = snd_pcm_hw_params_any(pcm->handle, pxmHwParams);
+    if (error < 0) {
+        AFB_ApiError(mixer->api, "%s: Failed to get parameters: %s", __func__, snd_strerror(error));
+        goto OnErrorExit;
+    }
+
+    AFB_ApiNotice(mixer->api, "PARAMS before:\n");
+    AlsaDumpPcmParams(mixer, pxmHwParams);
+
+    if (!opts->access)
+         opts->access = SND_PCM_ACCESS_RW_INTERLEAVED;
 
-    if (!opts->access) opts->access = SND_PCM_ACCESS_RW_INTERLEAVED;
     snd_pcm_hw_params_get_access(pxmHwParams, &access);
     error = snd_pcm_hw_params_set_access(pcm->handle, pxmHwParams, opts->access);
     if (error) {
-        AFB_ApiError(mixer->api, "AlsaPcmConf: mixer=%s cardid=%s Set_Interleave=%d Fail current=%d mode error=%s", mixer->uid, pcm->cid.cardid, opts->access, access, snd_strerror(error));
+        AFB_ApiError(mixer->api,
+                     "%s set_access failed (ignore this error): mixer=%s cardid=%s access=%d Fail current=%d mode error=%s",
+                     __func__, mixer->uid, pcm->cid.cardid, opts->access, access, snd_strerror(error));
 //Fulup        goto OnErrorExit;
     };
 
     if (opts->format != SND_PCM_FORMAT_UNKNOWN) {
         snd_pcm_hw_params_get_format(pxmHwParams, &format);
         if ((error = snd_pcm_hw_params_set_format(pcm->handle, pxmHwParams, opts->format)) < 0) {
-            AFB_ApiError(mixer->api, "AlsaPcmConf: mixer=%s cardid=%s Set_Format=%d Fail current=%d error=%s", mixer->uid, pcm->cid.cardid, opts->format, format, snd_strerror(error));
+            AFB_ApiError(mixer->api,
+                         "%s: mixer=%s cardid=%s Set_Format=%s (%d) FAILED current=%d error=%s",
+                         __func__, mixer->uid, pcm->cid.cardid, opts->formatS, opts->format, format, snd_strerror(error));
             AlsaDumpFormats(mixer, pcm->handle);
             goto OnErrorExit;
         }
@@ -102,8 +122,6 @@ PUBLIC int AlsaPcmConf(SoftMixerT *mixer, AlsaPcmCtlT *pcm, AlsaPcmHwInfoT *opts
         }
     }
 
-
-
     if (opts->channels) {
         if ((error = snd_pcm_hw_params_set_channels(pcm->handle, pxmHwParams, opts->channels)) < 0) {
             AFB_ApiError(mixer->api, "AlsaPcmConf: mixer=%s cardid=%s Set_Channels=%d Fail error=%s",mixer->uid, pcm->cid.cardid, opts->channels, snd_strerror(error));
@@ -111,19 +129,55 @@ PUBLIC int AlsaPcmConf(SoftMixerT *mixer, AlsaPcmCtlT *pcm, AlsaPcmHwInfoT *opts
         };
     }
 
+    int err;
+    unsigned buffer_time = 0;
+    unsigned period_time = 0;
+    snd_pcm_uframes_t buffer_frames = 0;
+    snd_pcm_uframes_t period_frames = 0;
+
+	err = snd_pcm_hw_params_get_buffer_time_max(pxmHwParams, &buffer_time, 0);
+	if (buffer_time > 500000)
+		buffer_time = 500000;
+
+	if (period_time == 0 && period_frames == 0) {
+		if (buffer_time > 0)
+			period_time = buffer_time / 4;
+		else
+			period_frames = buffer_frames / 4;
+	}
+	if (period_time > 0)
+		err = snd_pcm_hw_params_set_period_time_near(pcm->handle, pxmHwParams, &period_time, 0);
+	else
+		err = snd_pcm_hw_params_set_period_size_near(pcm->handle, pxmHwParams, &period_frames, 0);
+
+	assert(err >= 0);
+
+	if (buffer_time > 0) {
+		err = snd_pcm_hw_params_set_buffer_time_near(pcm->handle, pxmHwParams, &buffer_time, 0);
+	} else {
+		err = snd_pcm_hw_params_set_buffer_size_near(pcm->handle, pxmHwParams, &buffer_frames);
+	}
+
+	assert(err >= 0);
+
     // store selected values
     if ((error = snd_pcm_hw_params(pcm->handle, pxmHwParams)) < 0) {
         AFB_ApiError(mixer->api, "AlsaPcmConf: mixer=%s cardid=%s Fail apply hwparams error=%s", mixer->uid, pcm->cid.cardid, snd_strerror(error));
         goto OnErrorExit;
     }
 
+    AFB_ApiNotice(mixer->api, "PARAMS after:\n");
+    AlsaDumpPcmParams(mixer, pxmHwParams);
+
     // check we effective hw params after optional format change
     snd_pcm_hw_params_get_channels(pxmHwParams, &opts->channels);
     snd_pcm_hw_params_get_format(pxmHwParams, &opts->format);
     snd_pcm_hw_params_get_rate(pxmHwParams, &opts->rate, 0);
     opts->sampleSize = AlsaPeriodSize(opts->format);
     if (opts->sampleSize == 0) {
-        AFB_ApiError(mixer->api, "AlsaPcmConf: mixer=%s cardid=%s Fail unsupported format format=%d", mixer->uid, pcm->cid.cardid, opts->format);
+        AFB_ApiError(mixer->api,
+                     "%s: mixer=%s cardid=%s Fail unsupported format format=%d",
+                     __func__, mixer->uid, pcm->cid.cardid, opts->format);
         goto OnErrorExit;
     }
 
@@ -131,14 +185,16 @@ PUBLIC int AlsaPcmConf(SoftMixerT *mixer, AlsaPcmCtlT *pcm, AlsaPcmHwInfoT *opts
     snd_pcm_sw_params_alloca(&pxmSwParams);
     snd_pcm_sw_params_current(pcm->handle, pxmSwParams);
 
-    if ((error = snd_pcm_sw_params_set_avail_min(pcm->handle, pxmSwParams, 16)) < 0) {
-        AFB_ApiError(mixer->api, "AlsaPcmConf: mixer=%s cardid=%s Fail set_buffersize error=%s", mixer->uid, pcm->cid.cardid, snd_strerror(error));
+    if ((error = snd_pcm_sw_params_set_avail_min(pcm->handle, pxmSwParams, 1024)) < 0) {
+        AFB_ApiError(mixer->api,
+                     "%s: mixer=%s cardid=%s Fail set_buffersize error=%s",
+					 __func__, mixer->uid, pcm->cid.cardid, snd_strerror(error));
         goto OnErrorExit;
     };
 
     // push software params into PCM
     if ((error = snd_pcm_sw_params(pcm->handle, pxmSwParams)) < 0) {
-        AFB_ApiError(mixer->api, "AlsaPcmConf: mixer=%s cardid=%s Fail to push params error=%s", mixer->uid, pcm->cid.cardid, snd_strerror(error));
+        AFB_ApiError(mixer->api, "AlsaPcmConf: mixer=%s cardid=%s Fail to push SW params error=%s", mixer->uid, pcm->cid.cardid, snd_strerror(error));
         goto OnErrorExit;
     };
 
@@ -149,16 +205,17 @@ OnErrorExit:
     return -1;
 }
 
-
 STATIC int AlsaPcmReadCB(sd_event_source* src, int fd, uint32_t revents, void* userData) {
     char string[32];
-    int error;
-    snd_pcm_sframes_t framesIn, framesOut, availIn, availOut;
+
+    snd_pcm_sframes_t framesIn, framesOut, availIn, availOut, readIn;
     AlsaPcmCopyHandleT *pcmCopyHandle = (AlsaPcmCopyHandleT*) userData;
 
     // PCM has was closed
     if ((revents & EPOLLHUP) != 0) {
-        AFB_ApiNotice(pcmCopyHandle->api, "AlsaPcmReadCB PCM=%s hanghup/disconnected", ALSA_PCM_UID(pcmCopyHandle->pcmIn, string));
+        AFB_ApiNotice(pcmCopyHandle->api,
+                      "%s PCM=%s hanghup/disconnected",
+                      __func__, ALSA_PCM_UID(pcmCopyHandle->pcmIn, string));
         goto ExitOnSuccess;
     }
 
@@ -167,75 +224,85 @@ STATIC int AlsaPcmReadCB(sd_event_source* src, int fd, uint32_t revents, void* u
         goto ExitOnSuccess;
     }
 
-    // retrieve PCM state
-    snd_pcm_state_t pcmState = snd_pcm_state(pcmCopyHandle->pcmIn);
-    
-    // When pause flush remaining frame and wait
-    if (pcmState == SND_PCM_STATE_PAUSED) {
-        framesIn = snd_pcm_readi(pcmCopyHandle->pcmIn, pcmCopyHandle->buffer, pcmCopyHandle->frameCount);
-        AFB_ApiInfo(pcmCopyHandle->api, "AlsaPcmReadCB: paused frame:%ld ignored", framesIn);
-        goto ExitOnSuccess;
-    }
-
-    // When XRNS append try to restore PCM
-    if (pcmState == SND_PCM_STATE_XRUN) {
-        AFB_ApiNotice(pcmCopyHandle->api, "AlsaPcmReadCB PCM=%s XRUN", ALSA_PCM_UID(pcmCopyHandle->pcmIn, string));
-        snd_pcm_prepare(pcmCopyHandle->pcmIn);
-    }
-
-    // when PCM suspending loop until ready to go
-    if (pcmState == SND_PCM_STATE_SUSPENDED) {
-        while (1) {
-            if ((error = snd_pcm_resume(pcmCopyHandle->pcmIn)) < 0) {
-                AFB_ApiNotice(pcmCopyHandle->api, "AlsaPcmReadCB PCM=%s SUSPENDED fail to resume", ALSA_PCM_UID(pcmCopyHandle->pcmIn, string));
-                sleep(1); // Fulup should be replace with corresponding AFB_timer
-            } else {
-                AFB_ApiNotice(pcmCopyHandle->api, "AlsaPcmReadCB PCM=%s SUSPENDED success to resume", ALSA_PCM_UID(pcmCopyHandle->pcmIn, string));
-            }
-        }
-    }
-
     // do we have waiting frame
     availIn = snd_pcm_avail_update(pcmCopyHandle->pcmIn);
     if (availIn <= 0) {
+        if (availIn == -EPIPE) {
+            xrun(pcmCopyHandle->pcmIn);
+    	}
         goto ExitOnSuccess;
     }
 
     // do we have space to push frame
     availOut = snd_pcm_avail_update(pcmCopyHandle->pcmOut);
-    if (availOut <= 0) {
-        snd_pcm_prepare(pcmCopyHandle->pcmOut);
-        goto ExitOnSuccess;
+    if (availOut < 0) {
+        if (availOut == -EPIPE) {
+            xrun(pcmCopyHandle->pcmOut);
+            goto ExitOnSuccess;
+    	}
+    	if (availOut == -ESTRPIPE) {
+            suspend(pcmCopyHandle->pcmOut);
+            goto ExitOnSuccess;
+    	}
     }
 
+    if (availOut == 0)
+        goto ExitOnSuccess;
+
+    readIn = availIn;
+
     // make sure we can push all input frame into output pcm without locking
-    if (availOut < availIn) availIn = availOut;
+    if (readIn > availOut)
+    	readIn = availOut;
 
     // we get too many data ignore some
-    if (availIn > pcmCopyHandle->frameCount) {
-        availIn = pcmCopyHandle->frameCount;
+    if (readIn > pcmCopyHandle->buf_size) {
+    	readIn = pcmCopyHandle->buf_size;
     }
 
     // effectively read pcmIn and push frame to pcmOut
-    framesIn = snd_pcm_readi(pcmCopyHandle->pcmIn, pcmCopyHandle->buffer, availIn);
-    if (framesIn < 0 || framesIn != availIn) {
-        AFB_ApiNotice(pcmCopyHandle->api, "AlsaPcmReadCB PcmIn=%s UNDERUN framesIn=%ld, availIn %ld, max %d",
-                      ALSA_PCM_UID(pcmCopyHandle->pcmIn, string), framesIn, availIn, pcmCopyHandle->frameCount);
-        snd_pcm_prepare(pcmCopyHandle->pcmIn);
+    framesIn = snd_pcm_readi(pcmCopyHandle->pcmIn, pcmCopyHandle->buf, readIn);
+    if (framesIn < 0 || framesIn != readIn) {
+        AFB_ApiNotice(pcmCopyHandle->api,
+                      "%s PcmIn=%s READ UNDERUN framesIn=%ld, availIn %ld, max %ld, err %s",
+                      __func__, ALSA_PCM_UID(pcmCopyHandle->pcmIn, string), framesIn, readIn, pcmCopyHandle->buf_count,  snd_strerror((int)framesIn));
+        xrun(pcmCopyHandle->pcmIn);
         goto ExitOnSuccess;
     }
 
-    // In/Out frames transfer through buffer copy
-    framesOut = snd_pcm_writei(pcmCopyHandle->pcmOut, pcmCopyHandle->buffer, framesIn);
-    //framesOut = snd_pcm_mmap_writei (pcmCopyHandle->pcmOut, pcmCopyHandle->buffer, framesIn);
-    if (framesOut < 0 || framesOut != framesIn) {
-        AFB_ApiNotice(pcmCopyHandle->api, "AlsaPcmReadCB PcmOut=%s UNDERUN frame=%ld=>%ld error=%s", ALSA_PCM_UID(pcmCopyHandle->pcmOut, string), framesOut ,framesIn, snd_strerror((int)framesOut));
-        snd_pcm_prepare(pcmCopyHandle->pcmOut);
-        goto ExitOnSuccess;
+    unsigned long count = framesIn;
+    char * data = pcmCopyHandle->buf;
+
+    while (count > 0) {
+    	// In/Out frames transfer through buffer copy
+
+    	framesOut = snd_pcm_writei(pcmCopyHandle->pcmOut, data, count);
+
+    	if (framesOut == -EAGAIN) {
+    		printf("Write EAGAIN\n");
+    		snd_pcm_wait(pcmCopyHandle->pcmOut, 100);
+    		goto ExitOnSuccess;
+    	}
+    	if (framesOut == -EPIPE) {
+    		xrun(pcmCopyHandle->pcmOut);
+    		goto ExitOnSuccess;
+    	}
+    	if (framesOut == -ESTRPIPE) {
+    		suspend(pcmCopyHandle->pcmOut);
+    		goto ExitOnSuccess;
+    	}
+    	if (framesOut < 0 ) {
+    		printf("UNKNOWN ERROR\n");
+    		goto ExitOnSuccess;
+    	}
+    	count -= framesOut;
+    	data  += framesOut * pcmCopyHandle->frame_size;
     }
 
     if (framesIn != framesOut) {
-        AFB_ApiNotice(pcmCopyHandle->api, "AlsaPcmReadCB PCM=%s Loosing frames=%ld", ALSA_PCM_UID(pcmCopyHandle->pcmOut, string), (framesIn - framesOut));
+        AFB_ApiNotice(pcmCopyHandle->api,
+                      "%s PCM=%s Loosing frames=%ld",
+                      __func__, ALSA_PCM_UID(pcmCopyHandle->pcmOut, string), (framesIn - framesOut));
         goto ExitOnSuccess;
     }
     
@@ -246,30 +313,72 @@ ExitOnSuccess:
     return 0;
 }
 
+
+static int xrun( snd_pcm_t * pcm)
+{
+	int err;
+
+	printf("xrun !\n");
+
+	if ((err = snd_pcm_prepare(pcm)) < 0) {
+		printf("xrun: prepare failed\n");
+		return err;
+	}
+
+	return 0;
+}
+
+static int suspend( snd_pcm_t * pcm)
+{
+	int err;
+
+	printf("suspend !\n");
+
+	while ((err = snd_pcm_resume(pcm)) == -EAGAIN) {
+		printf("%s: again\n", __func__);
+		usleep(1);
+	}
+	if (err < 0)
+		return xrun(pcm);
+	return 0;
+}
+
+
 static void *LoopInThread(void *handle) {
     AlsaPcmCopyHandleT *pcmCopyHandle = (AlsaPcmCopyHandleT*) handle;
     int count = 0;
     int watchdog = MAINLOOP_WATCHDOG * 1000;
     pcmCopyHandle->tid = (int) syscall(SYS_gettid);
 
-    AFB_ApiNotice(pcmCopyHandle->api, "LoopInThread:%s/%d Started", pcmCopyHandle->info, pcmCopyHandle->tid);
-
+    AFB_ApiNotice(pcmCopyHandle->api,
+                  "%s :%s/%d Started",
+                  __func__, pcmCopyHandle->info, pcmCopyHandle->tid);
 
     /* loop until end */
     for (;;) {
         int res = sd_event_run(pcmCopyHandle->sdLoop, watchdog);
         if (res == 0) {
-            AFB_ApiInfo(pcmCopyHandle->api, "LoopInThread:%s/%d Idle count=%d", pcmCopyHandle->info, pcmCopyHandle->tid, count++);
+            AFB_ApiInfo(pcmCopyHandle->api,
+                        "%s:%s/%d Idle count=%d",
+                        __func__, pcmCopyHandle->info, pcmCopyHandle->tid, count++);
             continue;
         }
         if (res < 0) {
-            AFB_ApiError(pcmCopyHandle->api, "LoopInThread:%s/%d ERROR=%i Exit errno=%s.\n", pcmCopyHandle->info, pcmCopyHandle->tid, res, strerror(res));
+            AFB_ApiError(pcmCopyHandle->api,
+                         "%s:%s/%d ERROR=%i Exit errno=%s.\n",
+                         __func__, pcmCopyHandle->info, pcmCopyHandle->tid, res, strerror(res));
             break;
         }
     }
     pthread_exit(0);
 }
 
+static inline snd_pcm_uframes_t time_to_frames(unsigned int rate,
+					       unsigned long long time)
+{
+	return (time * rate) / 1000000ULL;
+}
+
 PUBLIC int AlsaPcmCopy(SoftMixerT *mixer, AlsaStreamAudioT *stream, AlsaPcmCtlT *pcmIn, AlsaPcmCtlT *pcmOut, AlsaPcmHwInfoT * opts) {
     char string[32];
     struct pollfd *pcmInFds; 
@@ -277,69 +386,113 @@ PUBLIC int AlsaPcmCopy(SoftMixerT *mixer, AlsaStreamAudioT *stream, AlsaPcmCtlT
     
     // Fulup need to check https://www.alsa-project.org/alsa-doc/alsa-lib/group___p_c_m___direct.html
     
-    //AlsaDumpPcmInfo(mixer,"PcmIn",pcmIn->handle);
-    //AlsaDumpPcmInfo(mixer,"PcmOut",pcmOut->handle);
+    AlsaDumpPcmInfo(mixer,"PcmIn",pcmIn->handle);
+    AlsaDumpPcmInfo(mixer,"PcmOut",pcmOut->handle);
+
+    AFB_ApiInfo(mixer->api, "%s: Configure CAPTURE PCM", __func__);
 
     // prepare PCM for capture and replay
-    error = AlsaPcmConf(mixer, pcmIn, opts);
-    if (error) goto OnErrorExit;
+    error = AlsaPcmConf(mixer, pcmIn, opts, SND_PCM_STREAM_CAPTURE);
+    if (error) {
+    	AFB_ApiError(mixer->api, "%s: PCM configuration for capture failed", __func__);
+    	goto OnErrorExit;
+    }
     
+    AFB_ApiInfo(mixer->api, "%s: Configure PLAYBACK PCM", __func__);
+
     // input and output should match
-    error = AlsaPcmConf(mixer, pcmOut, opts);
-    if (error) goto OnErrorExit;
+    error = AlsaPcmConf(mixer, pcmOut, opts, SND_PCM_STREAM_PLAYBACK);
+    if (error) {
+    	AFB_ApiError(mixer->api, "%s: PCM configuration for playback failed", __func__);
+    	goto OnErrorExit;
+    }
 
     // Prepare PCM for usage
     if ((error = snd_pcm_prepare(pcmOut->handle)) < 0) {
-        AFB_ApiError(mixer->api, "AlsaPcmCopy: Fail to prepare PCM=%s error=%s", ALSA_PCM_UID(pcmOut->handle, string), snd_strerror(error));
+        AFB_ApiError(mixer->api, "%s: Fail to prepare PLAYBACK PCM=%s error=%s", __func__, ALSA_PCM_UID(pcmOut->handle, string), snd_strerror(error));
         goto OnErrorExit;
     };
 
     // Prepare PCM for usage
+    if ((error = snd_pcm_prepare(pcmIn->handle)) < 0) {
+        AFB_ApiError(mixer->api, "%s: Fail to prepare CAPTURE PCM=%s error=%s", __func__, ALSA_PCM_UID(pcmOut->handle, string), snd_strerror(error));
+        goto OnErrorExit;
+    };
+
+    // Start PCM
+    if ((error = snd_pcm_start(pcmOut->handle)) < 0) {
+        AFB_ApiError(mixer->api, "%s: Fail to start PLAYBACK PCM=%s error=%s", __func__, ALSA_PCM_UID(pcmIn->handle, string), snd_strerror(error));
+        goto OnErrorExit;
+    };
+
+    // Start PCM
     if ((error = snd_pcm_start(pcmIn->handle)) < 0) {
-        AFB_ApiError(mixer->api, "AlsaPcmCopy: Fail to prepare PCM=%s error=%s", ALSA_PCM_UID(pcmIn->handle, string), snd_strerror(error));
+        AFB_ApiError(mixer->api, "%s: Fail to start CAPTURE PCM=%s error=%s", __func__, ALSA_PCM_UID(pcmIn->handle, string), snd_strerror(error));
         goto OnErrorExit;
     };
     
     AlsaPcmCopyHandleT *cHandle= calloc(1, sizeof(AlsaPcmCopyHandleT));
-    cHandle = cHandle;
+
     cHandle->info = "pcmCpy";
     cHandle->pcmIn = pcmIn->handle;
     cHandle->pcmOut = pcmOut->handle;
     cHandle->api = mixer->api;
     cHandle->channels = opts->channels;
-    cHandle->frameSize = opts->channels * opts->sampleSize;
-    cHandle->frameCount = ALSA_BUFFER_FRAMES_COUNT;
-    cHandle->buffer = malloc(cHandle->frameCount * cHandle->frameSize);
+
+    cHandle->latency_reqtime = 10000;
+    cHandle->latency = time_to_frames(opts->rate, cHandle->latency_reqtime);
+    AFB_ApiInfo(mixer->api, "%s: Latency = %ld", __func__, cHandle->latency);
+
+	cHandle->frame_size = (snd_pcm_format_physical_width(opts->format) / 8) * opts->channels;
+
+	AFB_ApiInfo(mixer->api, "%s: Frame size is %zu", __func__, cHandle->frame_size);
+
+    size_t size = cHandle->latency * 2;
+    cHandle->buf = calloc(1, size*cHandle->frame_size);
+    cHandle->buf_count = 0;
+    cHandle->buf_size = size;
     
+    AFB_ApiInfo(mixer->api, "%s Copy buf size is %zu", __func__, size);
+
     // get FD poll descriptor for capture PCM
     int pcmInCount = snd_pcm_poll_descriptors_count(cHandle->pcmIn);
     if (pcmInCount <= 0) {
-        AFB_ApiError(mixer->api, "AlsaPcmCopy: Fail pcmIn=%s get fds count error=%s", ALSA_PCM_UID(pcmIn->handle, string), snd_strerror(error));
+        AFB_ApiError(mixer->api,
+                     "%s: Fail pcmIn=%s get fds count error=%s",
+                     __func__, ALSA_PCM_UID(pcmIn->handle, string), snd_strerror(error));
         goto OnErrorExit;
     };
 
     pcmInFds = alloca(sizeof (*pcmInFds) * pcmInCount);
     if ((error = snd_pcm_poll_descriptors(pcmIn->handle, pcmInFds, pcmInCount)) < 0) {
-        AFB_ApiError(mixer->api, "AlsaPcmCopy: Fail pcmIn=%s get pollfds error=%s", ALSA_PCM_UID(pcmOut->handle, string), snd_strerror(error));
+        AFB_ApiError(mixer->api,
+                     "%s: Fail pcmIn=%s get pollfds error=%s",
+                     __func__, ALSA_PCM_UID(pcmOut->handle, string), snd_strerror(error));
         goto OnErrorExit;
     };
 
     // add poll descriptor to AGL systemd mainloop
     if ((error = sd_event_new(&cHandle->sdLoop)) < 0) {
-        fprintf(stderr, "LaunchCallRequest: fail pcmin=%s creating a new loop: %s\n", ALSA_PCM_UID(pcmOut->handle, string), strerror(error));
+    	AFB_ApiError(mixer->api,
+    			     "%s: fail pcmin=%s creating a new loop: %s\n",
+                     __func__, ALSA_PCM_UID(pcmOut->handle, string), strerror(error));
         goto OnErrorExit;
     }
 
     for (int idx = 0; idx < pcmInCount; idx++) {
         if ((error = sd_event_add_io(cHandle->sdLoop, &cHandle->evtsrc, pcmInFds[idx].fd, EPOLLIN, AlsaPcmReadCB, cHandle)) < 0) {
-            AFB_ApiError(mixer->api, "AlsaPcmCopy: Fail pcmIn=%s sd_event_add_io err=%d", ALSA_PCM_UID(pcmIn->handle, string), error);
+            AFB_ApiError(mixer->api,
+                         "%s: Fail pcmIn=%s sd_event_add_io err=%d",
+                         __func__, ALSA_PCM_UID(pcmIn->handle, string), error);
             goto OnErrorExit;
         }
     }
 
     // start a thread with a mainloop to monitor Audio-Agent
     if ((error = pthread_create(&cHandle->thread, NULL, &LoopInThread, cHandle)) < 0) {
-        AFB_ApiError(mixer->api, "AlsaPcmCopy: Fail create waiting thread pcmIn=%s err=%d", ALSA_PCM_UID(pcmIn->handle, string), error);
+        AFB_ApiError(mixer->api,
+                     "%s Fail create waiting thread pcmIn=%s err=%d",
+                     __func__, ALSA_PCM_UID(pcmIn->handle, string), error);
         goto OnErrorExit;
     }
     
@@ -348,14 +501,15 @@ PUBLIC int AlsaPcmCopy(SoftMixerT *mixer, AlsaStreamAudioT *stream, AlsaPcmCtlT
     params.sched_priority = sched_get_priority_max(SCHED_FIFO);
     error= pthread_setschedparam(cHandle->thread, SCHED_FIFO, &params);
     if (error) {
-        AFB_ApiWarning(mixer->api, "AlsaPcmCopy: Fail create increase stream thread priority pcmIn=%s err=%s", ALSA_PCM_UID(pcmIn->handle, string), strerror(error));        
+        AFB_ApiWarning(mixer->api,
+                       "%s: Failed to increase stream thread priority pcmIn=%s err=%s",
+                       __func__, ALSA_PCM_UID(pcmIn->handle, string), strerror(error));
     }
-
     return 0;
 
 OnErrorExit:
-    AFB_ApiError(mixer->api, "AlsaPcmCopy: - pcmIn=%s" , ALSA_PCM_UID(pcmIn->handle, string));
-    AFB_ApiError(mixer->api, "AlsaPcmCopy: - pcmOut=%s", ALSA_PCM_UID(pcmOut->handle, string));
+    AFB_ApiError(mixer->api, "%s: - pcmIn=%s" , __func__, ALSA_PCM_UID(pcmIn->handle, string));
+    AFB_ApiError(mixer->api, "%s: - pcmOut=%s", __func__, ALSA_PCM_UID(pcmOut->handle, string));
     return -1;
 }
 
diff --git a/plugins/alsa/alsa-softmixer.h b/plugins/alsa/alsa-softmixer.h
index f435b3f..6c1519d 100644
--- a/plugins/alsa/alsa-softmixer.h
+++ b/plugins/alsa/alsa-softmixer.h
@@ -28,6 +28,7 @@
 #include <stdio.h>
 #include <assert.h>
 #include <alsa/asoundlib.h>
+#include <stdbool.h>
 
 #include "ctl-plugin.h"
 #include "wrap-json.h"
@@ -44,7 +45,7 @@
 #define MAINLOOP_WATCHDOG 30000
 #define ALSA_DEFAULT_PCM_RATE 48000
 #define ALSA_DEFAULT_PCM_VOLUME 80
-#define ALSA_BUFFER_FRAMES_COUNT 1024
+
 #define ALSA_CARDID_MAX_LEN 64
 
 
@@ -82,14 +83,22 @@ typedef struct {
     snd_pcm_t *pcmOut;
     AFB_ApiT api;
     sd_event_source* evtsrc;
-    void* buffer;
-    size_t frameSize;
-    unsigned int frameCount;
+
+    size_t frame_size;
+    snd_pcm_uframes_t latency;	/* final latency in frames */
+	unsigned int latency_reqtime;	/* in us */
+
+    // IO Job
+    void * buf;
+	snd_pcm_uframes_t buf_count;	/* filled samples */
+	snd_pcm_uframes_t buf_size;	/* buffer size in frames */
+
     unsigned int channels;
     sd_event *sdLoop;
     pthread_t thread;
     int tid;
     char* info;
+
 } AlsaPcmCopyHandleT;
 
 typedef struct {
@@ -137,6 +146,7 @@ typedef struct {
     AlsaDevInfoT cid;
     snd_pcm_t *handle;
     AlsaPcmHwInfoT *params;
+    uint32_t avail_min;
 } AlsaPcmCtlT;
 
 typedef struct {
@@ -258,12 +268,10 @@ PUBLIC int AlsaCtlSubscribe(SoftMixerT *mixer, const char *uid, AlsaSndCtlT *snd
 PUBLIC int AlsaCtlRegister(SoftMixerT *mixer, AlsaSndCtlT *sndcard, AlsaPcmCtlT *pcmdev,  RegistryNumidT type, int numid);
 
 // alsa-core-pcm.c
-PUBLIC int AlsaPcmConf(SoftMixerT *mixer, AlsaPcmCtlT *pcm, AlsaPcmHwInfoT *opts);
+PUBLIC int AlsaPcmConf(SoftMixerT *mixer, AlsaPcmCtlT *pcm, AlsaPcmHwInfoT *opts, int mode);
 PUBLIC int AlsaPcmCopy(SoftMixerT *mixer, AlsaStreamAudioT *stream, AlsaPcmCtlT *pcmIn, AlsaPcmCtlT *pcmOut, AlsaPcmHwInfoT * opts);
 
-
 // alsa-plug-*.c _snd_pcm_PLUGIN_open_ see macro ALSA_PLUG_PROTO(plugin)
-PUBLIC int AlsaPcmConf(SoftMixerT *mixer, AlsaPcmCtlT *pcm, AlsaPcmHwInfoT *opts);
 PUBLIC int AlsaPcmCopy(SoftMixerT *mixer, AlsaStreamAudioT *streamAudio, AlsaPcmCtlT *pcmIn, AlsaPcmCtlT *pcmOut, AlsaPcmHwInfoT * opts);
 PUBLIC AlsaPcmCtlT* AlsaCreateSoftvol(SoftMixerT *mixer, AlsaStreamAudioT *stream, char *slaveid, AlsaSndCtlT *sndcard, char* ctlName, int max, int open);
 PUBLIC AlsaPcmCtlT* AlsaCreateRoute(SoftMixerT *mixer, AlsaSndZoneT *zone, int open);
@@ -290,4 +298,4 @@ PUBLIC int ApiZoneAttach(SoftMixerT *mixer, AFB_ReqT request, const char *uid, j
 PUBLIC AlsaVolRampT *ApiRampGetByUid(SoftMixerT *mixer, const char *uid);
 PUBLIC int AlsaVolRampApply(SoftMixerT *mixer, AlsaSndCtlT *sndcard, AlsaStreamAudioT *stream, json_object *rampJ);
 
-#endif
\ No newline at end of file
+#endif