[alsa-devel] snd_pcm_mmap_commit
/*************************************************************/ Code below O/p results runs in a while loop till end of PCM data. 1) First time O/p is Farames available : 1024 /*Return VALUE of snd_pcm_avail_update*/ >>>>>>>>>>>>>>>>>>>>>>>>>Begin result : 0 /*Return VALUE of snd_pcm_mmap_begin*/ Address outbuffer : 0xcff88 >>>>>>>>>>>>>>>>>>>>>>Comit result : 1024 /*SUCESSFUL - Return VALUE of snd_pcm_mmap_commi*/
2) Second time onwards ALWAYS O/p is Farames available : 0 /*Return VALUE of snd_pcm_avail_update*/ >>>>>>>>>>>>>>>>>>>>>>>>>Begin result : 0 /*Return VALUE of snd_pcm_mmap_begin*/ Address outbuffer : 0xcff88 >>>>>>>>>>>>>>>>>>>>>>Comit result : 0 /*FAILURE - Return VALUE of snd_pcm_mmap_commit*/ . . . . . . N) Nth time Farames available : 0 /*Return VALUE of snd_pcm_avail_update*/ >>>>>>>>>>>>>>>>>>>>>>>>>Begin result : 0 /*Return VALUE of snd_pcm_mmap_begin*/ Address outbuffer : 0xcff88 >>>>>>>>>>>>>>>>>>>>>>Comit result : 0 /*FAILURE - Return VALUE of snd_pcm_mmap_commit*/ . /*************************************************************/ +++++++++++++++ Why second time onwards I get the above behavious what am i missing ? Please HELP ! +++++++++++++++
############ MY CODE #############
#ifdef DIRECT snd_pcm_sframes_t frames_available, frames_transmit; const snd_pcm_channel_area_t *area; snd_pcm_uframes_t offset; unsigned char *outbuffer; int result,i;
/*available space in audio-buffer to write to*/ frames_available = snd_pcm_avail_update(alsaParams->pcm_handle); printf("Farames available : %d\n", frames_available);
/* * prepare the areas * and get back area, offset and frames_transmit * frames_transmit gives back the REAL value of available frames which could be written to in the mmaped-area * frames_transmit are less than frames_available */ frames_transmit = frames_available;
if( 0 > ( result = snd_pcm_mmap_begin(alsaParams->pcm_handle, &area, &offset, &frames_transmit))) { printf("===========================>>>>>>>>>>>>>>>>>>>>>snd_pcm_mmap_begin_error\n"); xrun_recovery(alsaParams->pcm_handle, pcmreturn); return; //return xrun_recovery(); }
printf(">>>>>>>>>>>>>>>>>>>>>>>>>Begin result : %d\n", result); utbuffer = ((char *) area->addr + (area->first + area->step * offset)/ 8); printf("Address outbuffer : %p\n", outbuffer);
memcpy(outbuffer, data, count); //data is actual data
/*gives back the virtually written (writable) frames which should be always == frames_transmit*/ if( 0 > ( result = snd_pcm_mmap_commit(alsaParams->pcm_handle, offset, frames_transmit))) { printf("==============================>>>>>>>>>>>>>>>>>>>>>>>>snd_pcm_mmap_commit error\n"); xrun_recovery(alsaParams->pcm_handle, pcmreturn); return; //return xrun_recovery(); } printf(">>>>>>>>>>>>>>>>>>>>>>Comit result : %d\n", result); #endif
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On Fri, 19 Nov 2010, Irfan Shaikh wrote:
/*************************************************************/ Code below O/p results runs in a while loop till end of PCM data.
First time O/p is Farames available : 1024 /*Return VALUE of snd_pcm_avail_update*/ >>>>>>>>>>>>>>>>>>>>>>>>>Begin result : 0 /*Return VALUE of snd_pcm_mmap_begin*/ Address outbuffer : 0xcff88 >>>>>>>>>>>>>>>>>>>>>>Comit result : 1024 /*SUCESSFUL - Return VALUE of snd_pcm_mmap_commi*/
Second time onwards ALWAYS O/p is Farames available : 0 /*Return VALUE of snd_pcm_avail_update*/ >>>>>>>>>>>>>>>>>>>>>>>>>Begin result : 0 /*Return VALUE of snd_pcm_mmap_begin*/ Address outbuffer : 0xcff88 >>>>>>>>>>>>>>>>>>>>>>Comit result : 0 /*FAILURE - Return VALUE of snd_pcm_mmap_commit*/
You have to use poll()/select() or snd_pcm_wait() to wait for a room in the playback buffer. The direct mmap I/O is always non-blocked.
Jaroslav
----- Jaroslav Kysela perex@perex.cz Linux Kernel Sound Maintainer ALSA Project, Red Hat, Inc.
As per your valuable inputs modified code using snd_pcm_wait /$$$$ My code waits indefinetly in snd_pcm_wait() $$$$$/ If i set some timer again frames available shows to be zero.
#ifdef DIRECT1 snd_pcm_state_t state; int err, first = 1; snd_pcm_sframes_t frames_available, frames_transmit,commitres; snd_pcm_uframes_t size, offset; unsigned char *outbuffer; const snd_pcm_channel_area_t *area; static int irf=0;
state = snd_pcm_state(alsaParams->pcm_handle); if (state == SND_PCM_STATE_XRUN) { err=xrun_recovery(alsaParams->pcm_handle, -EPIPE); if (err < 0) { printf("XRUN recovery failed: %s\n", snd_strerror(err)); exit(EXIT_FAILURE); } first = 1; } else if (state == SND_PCM_STATE_SUSPENDED) { err = xrun_recovery(alsaParams->pcm_handle, -ESTRPIPE); if (err < 0) { printf("SUSPEND recovery failed: %s\n", snd_strerror(err)); exit(EXIT_FAILURE); } } frames_available = snd_pcm_avail_update(alsaParams->pcm_handle); if (frames_available < 0) { err = xrun_recovery(alsaParams->pcm_handle, frames_available); if (err < 0) { printf("avail update failed: %s\n", snd_strerror(err)); exit(EXIT_FAILURE); } first = 1; printf("RETURN : Should Be continued\n"); return; } printf("Farames available : %d\n", frames_available); if(frames_available<=0) { #if 1 err = snd_pcm_wait(alsaParams->pcm_handle, -1); /############ WAIT here indefinitely ##############/ if (err < 0) { if ((err = xrun_recovery(alsaParams->pcm_handle, err)) < 0) { printf("snd_pcm_wait error: %s\n", snd_strerror(err)); exit(EXIT_FAILURE); } } #endif irf=1; return; } else if(irf==1) { err = snd_pcm_start(alsaParams->pcm_handle); if (err < 0) { printf("Start error: %s\n", snd_strerror(err)); exit(EXIT_FAILURE); } irf=0; } size=frames_available; while (size > 0) { frames_transmit = size; err=snd_pcm_mmap_begin(alsaParams->pcm_handle, &area, &offset, &frames_transmit); if (err < 0) { if ((err = xrun_recovery(alsaParams->pcm_handle, err)) < 0) { printf("MMAP begin avail error: %s\n", snd_strerror(err)); exit(EXIT_FAILURE); } first = 1; } printf(">>>>Begin result : %d\n", err); outbuffer = ((char *) area->addr + (area->first + area->step * offset)/ 8); //Copies Actual data
commitres = snd_pcm_mmap_commit(alsaParams->pcm_handle, offset, frames_transmit); if (commitres < 0 || (snd_pcm_uframes_t)commitres != frames_transmit) { if ((err = xrun_recovery(alsaParams->pcm_handle, commitres >= 0 ? -EPIPE : commitres)) < 0) { printf("MMAP commit error: %s\n", snd_strerror(err)); exit(EXIT_FAILURE); } first = 1; } printf(">>>>>>>>>>>>>>>>>>>>>>Comit result : %d\n", commitres); size -= frames_transmit; } #endif
________________________________________ From: Jaroslav Kysela [perex@perex.cz] Sent: Friday, November 19, 2010 12:41 PM To: Irfan Shaikh Cc: alsa-devel@alsa-project.org Subject: Re: [alsa-devel] snd_pcm_mmap_commit
On Fri, 19 Nov 2010, Irfan Shaikh wrote:
/*************************************************************/ Code below O/p results runs in a while loop till end of PCM data.
First time O/p is Farames available : 1024 /*Return VALUE of snd_pcm_avail_update*/ >>>>>>>>>>>>>>>>>>>>>>>>>Begin result : 0 /*Return VALUE of snd_pcm_mmap_begin*/ Address outbuffer : 0xcff88 >>>>>>>>>>>>>>>>>>>>>>Comit result : 1024 /*SUCESSFUL - Return VALUE of snd_pcm_mmap_commi*/
Second time onwards ALWAYS O/p is Farames available : 0 /*Return VALUE of snd_pcm_avail_update*/ >>>>>>>>>>>>>>>>>>>>>>>>>Begin result : 0 /*Return VALUE of snd_pcm_mmap_begin*/ Address outbuffer : 0xcff88 >>>>>>>>>>>>>>>>>>>>>>Comit result : 0 /*FAILURE - Return VALUE of snd_pcm_mmap_commit*/
You have to use poll()/select() or snd_pcm_wait() to wait for a room in the playback buffer. The direct mmap I/O is always non-blocked.
Jaroslav
----- Jaroslav Kysela perex@perex.cz Linux Kernel Sound Maintainer ALSA Project, Red Hat, Inc.
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participants (2)
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Irfan Shaikh -
Jaroslav Kysela