snd_register_device_for_dev 创建"pcmC%iD%ip"或者"pcmC%iD%ic"设备节点,它的fops为snd_pcm_f_ops[2] snd_pcm_f_ops[2] ==> snd_pcm_playback_open或者snd_pcm_capture_open ==> snd_pcm_open或者oss的snd_pcm_oss_f_reg.snd_pcm_oss_open,这就对应/dev/dsp了 ==> snd_pcm_open_file或者...
==> snd_pcm_open_conf(pcmp, name, root, conf, stream, mode); ==> open_func = snd_dlobj_cache_lookup(open_name);将获得lib库中_snd_pcm_empty_open函数 所以open_func将等于_snd_pcm_empty_open _snd_pcm_empty_open _snd_pcm_asym_open _snd_pcm_plug_open _snd_pcm_softvol_open _snd_...
==> snd_pcm_hw_open(pcmp, name, card, device, subdevice, stream, mode | (nonblock ? SND_PCM_NONBLOCK : 0), 0, sync_ptr_ioctl); ==> snd_ctl_hw_open filename等于"/dev/snd/controlC0" ==> snd_open_device(filename, fmode); ctl->ops = &snd_ctl_hw_ops; ctl->private_data...
==> snd_pcm_open_substream ==> soc_pcm_open /* ASoC PCM operations */ static struct snd_pcm_ops soc_pcm_ops = { .open = soc_pcm_open, .close = soc_codec_close, .hw_params = soc_pcm_hw_params, .hw_free = soc_pcm_hw_free, .prepare = soc_pcm_prepare, .trigger = soc_pc...
==> snd_pcm_playback_open或者snd_pcm_capture_open ==> snd_pcm_open或者oss的snd_pcm_oss_f_reg.snd_pcm_oss_open,这就对应/dev/dsp了 ==> snd_pcm_open_file或者oss的snd_pcm_oss_open_file ==> snd_pcm_open_substream ==> soc_pcm_open ...
==> snd_pcm_hw_open(pcmp, name, card, device, subdevice, stream, mode | (nonblock ? SND_PCM_NONBLOCK : 0), 0, sync_ptr_ioctl); ==> snd_ctl_hw_open filename等于"/dev/snd/controlC0" ==> snd_open_device(filename, fmode); ctl->ops = &snd_ctl_hw_ops; ctl->private_data...
snd_pcm_open 函数原型如下int snd_pcm_open(snd_pcm_t **pcmp, const char *name, snd_pcm_stream_t stream, int mode){ snd_config_t *top; int err; assert(pcmp && name); if (_snd_is_ucm_device(name)) { name = uc_mgr_alibcfg_by_device(&top, name); if (name == NULL) ...
打开PCM设备 设置硬件参数 读/写数据 PCM播放示例代码 PCM录音示例代码 使用异步方法 snd_async_add_pcm_handler()函数 snd_pcm_avail_update()函数 PCM异步播放示例 PCM异步录音示例 使用poll()函数 使用poll I/O多路复用实现读写 PCM播放示例 PCM录音示例 PCM设备状态 PCM播放——加入状态控制 snd_pcm_readi/...
alsa声卡/dev/snd/pcmC0D0p的open打开流程原文地址:/space.php?uid=20564848&do=blog&cuid=2116725aplay.c= main= snd_pcm_open(&handle, pcm_name, stream, open_mode); / 打开一路pcm,刷新config配置如果是default,同时type等于SND_CONFIG_TYPE_COMPOUND那么这里对应emptystatic const char *const build_in...
snd_pcm_set_ops(pcm,SNDRV_PCM_STREAM_CAPTURE,&soc_pcm_ops); ... } 在定义时初始化好的structsnd_pcm_ops结构体所指向的函数主要是通用函数(同时针对codec,codec_dai,platform、cpu_dai),而soc_new_pcm所赋值的函数主要是针对platform的函数。 我们看看...