I am trying to sent IEC958 status bits on a VT1708A HAD-INTEL codec while audio is being output. snd_ctl_elem_write returns -EPERM from linux-2.6.24.3/sound/core/control.c:769 .

Is there some way I can do this?

FYI using iecset will also give you an: # iecset copywrite on snd_ctl_elem_write: Operation not permitted

I am using alsa-lib-1.0.14a

$uname -a Linux vision-vs 2.6.24.3 #1 SMP Fri Mar 28 09:35:45 EDT 2008 i686 unknown

$ gcc -v Target: x86_64-linux-gnu Configured with: ../src/configure -v --enable-languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr --enable-shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --enable-nls --with-gxx-include-dir=/usr/include/c++/4.2 --program-suffix=-4.2 --enable-clocale=gnu --enable-libstdcxx-debug --enable-mpfr --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 4.2.3 20071123 (prerelease) (Debian 4.2.2-4)

If it helps, here is the code I am using to set the bits. I modeled this after the iecset.c code. Everything opens fine, it is the final call to "snd_ctl_elem_write(this->ctl_handle, cval))" that fails.

static int ao_alsa_set_spdif_status(ao_driver_t *this_gen, snd_aes_iec958_t* iec958) { alsa_driver_t *this = (alsa_driver_t *) this_gen; config_values_t *config = this->class->xine->config; char *pcm_device; snd_ctl_card_info_t *hw_info; int err; snd_pcm_info_t *pcm_info; int card; char card_name[20]; snd_ctl_elem_list_t *clist; snd_ctl_elem_id_t *cid; snd_ctl_elem_value_t *cval; unsigned int controls, cidx; const char *spdif_str = SND_CTL_NAME_IEC958("", PLAYBACK, DEFAULT); int opened_audio=0;

llprintf(LOG_TRACE_ENTER, "Entered\n");

if(!this->ctl_handle) { if (!this->audio_fd) { pcm_device = config->lookup_entry(config, "audio.device.alsa_passthrough_device")->str_value; llprintf(LOG_MIXER,"Calling local_snd_pcm_open(%s)\n", pcm_device);

err=local_snd_pcm_open(&this->audio_fd, pcm_device, SND_PCM_STREAM_PLAYBACK, 1); /* NON-BLOCK mode */ if ( err <0 ) { xine_log (this->class->xine, XINE_LOG_MSG,

_("local_snd_pcm_open() failed:%d:%s\n"), err, snd_strerror(err)); return -1; } opened_audio = 1; }

snd_pcm_info_alloca(&pcm_info); snd_pcm_info(this->audio_fd, pcm_info);

card = snd_pcm_info_get_card(pcm_info); llprintf(LOG_MIXER,"snd_pcm_info_get_card() returned %d\n", card); if(card < 0){ sprintf(card_name, "default"); } else{ sprintf(card_name, "hw:CARD=%i", card); }

if (opened_audio && this->audio_fd) { snd_pcm_close(this->audio_fd); this->audio_fd = NULL; opened_audio = 0; }

llprintf(LOG_MIXER,"Calling snd_ctl_open(%s)\n", card_name); if ( (err = snd_ctl_open (&this->ctl_handle, card_name, 0)) < 0 ) { xprintf (this->class->xine, XINE_VERBOSITY_DEBUG, "%s: snd_ctl_open(): %s\n", LOG_MODULE, snd_strerror(err)); return -1; } }

snd_ctl_card_info_alloca(&hw_info);

if ( (err = snd_ctl_card_info (this->ctl_handle, hw_info)) < 0 ) { xprintf (this->class->xine, XINE_VERBOSITY_DEBUG, "%s: snd_ctl_card_info(): %s\n", LOG_MODULE, snd_strerror(err)); snd_ctl_close(this->ctl_handle); this->ctl_handle = 0; return -1; }

/* set the spdif status bits */ snd_ctl_elem_list_alloca(&clist); if ((err = snd_ctl_elem_list(this->ctl_handle, clist)) < 0) { xprintf (this->class->xine, XINE_VERBOSITY_DEBUG, "snd_ctl_elem_list(): %s\n", snd_strerror(err)); snd_ctl_close(this->ctl_handle); this->ctl_handle = 0; return -1; } if ((err = snd_ctl_elem_list_alloc_space(clist, snd_ctl_elem_list_get_count(clist))) < 0) { xprintf (this->class->xine, XINE_VERBOSITY_DEBUG, "snd_ctl_elem_list_alloc_space(): %s\n", snd_strerror(err)); snd_ctl_close(this->ctl_handle); return -1; } if ((err = snd_ctl_elem_list(this->ctl_handle, clist)) < 0) { xprintf (this->class->xine, XINE_VERBOSITY_DEBUG, "snd_ctl_elem_list(): %s\n", snd_strerror(err)); snd_ctl_close(this->ctl_handle); this->ctl_handle = 0; return -1; }

controls = snd_ctl_elem_list_get_used(clist); for (cidx = 0; cidx < controls; cidx++) { if (!strcmp(snd_ctl_elem_list_get_name(clist, cidx), spdif_str)) break; } if (cidx >= controls) { fprintf(stderr, "control "%s" not found\n", spdif_str); snd_ctl_close(this->ctl_handle); this->ctl_handle = 0; return -1; }

snd_ctl_elem_id_alloca(&cid); snd_ctl_elem_list_get_id(clist, cidx, cid); snd_ctl_elem_value_alloca(&cval); snd_ctl_elem_value_set_id(cval, cid);

llprintf(LOG_MIXER,"Writing AES0=0x%02x,AES1=0x%02x,AES2=0x%02x,AES3=0x%02x\n", iec958->status[0], iec958->status[1], iec958->status[2], iec958->status[3]);

/* store the values */ snd_ctl_elem_value_set_iec958(cval, iec958); if ((err = snd_ctl_elem_write(this->ctl_handle, cval)) < 0) { xprintf (this->class->xine, XINE_VERBOSITY_DEBUG, "snd_ctl_elem_write(): %s\n", snd_strerror(err)); snd_ctl_close(this->ctl_handle); this->ctl_handle = 0; }

llprintf(LOG_MIXER,"snd_ctl_elem_write() returrned %d\n",err);

/*-------------------------------------------------------*/ /*snd_ctl_close (this->ctl_handle);*/

return 0; } ---------------------------------------------------- Bob Bouterse Sr. Software Engineer D&M Holdings Inc.