rc = snd_pcm_open(&handle, "default",SND_PCM_STREAM_PLAYBACK, 0);if (rc < 0) {fprintf(stderr,"unable to open pcm device: %s/n",snd_strerror(rc));exit(1);}/* Allocate a hardware parameters object. */snd_pcm_hw_params_alloca(?ms);/* Fill it in with default values. */snd...
snd_pcm_uframes_t frames;/* Open PCM device for playback. */rc = snd_pcm_open(&handle, "default", SND_PCM_STREAM_PLAYBACK, 0);if (rc < 0) { fprintf(stderr, "unable to open pcm device: %s/n", snd_strerror(rc)); exit(1);}/* Allocate a hardware parameters object. */snd_...
rc = snd_pcm_open(&handle, "default", SND_PCM_STREAM_PLAYBACK, 0); if (rc < 0) { fprintf(stderr, "unable to open pcm device: %s\n", snd_strerror(rc)); exit(1); } /* Allocate a hardware parameters object. */ snd_pcm_hw_params_alloca(¶ms); /* Fill it in with defaul...
staticintsnd_myctl_put(struct snd_kcontrol*kcontrol,struct snd_ctl_elem_value*ucontrol){struct mychip*chip=snd_kcontrol_chip(kcontrol);int changed=0;if(chip->current_value!=ucontrol->value.integer.value[0]){change_current_value(chip,ucontrol->value.integer.value[0]);changed=1;}returnchange...
*/wait_queue_head_t remove_sleep;#ifdefCONFIG_PMunsignedintpower_state;/* power state */wait_queue_head_t power_sleep;#endif#ifIS_ENABLED(CONFIG_SND_MIXER_OSS)structsnd_mixer_oss*mixer_oss;intmixer_oss_change_count;#endif}; struct list_head devices:记录该声卡下所有逻辑设备的链表; ...
根据声卡的实际能力,驱动实际上可以挂载更多种类的设备,在include/sound/core.h中,定义了以下设备类型,通常更关心的是pcm和control这两种设备,Default 一个声卡对应一个 Control 设备。 #defineSNDRV_DEV_TOPLEVEL ((__force snd_device_type_t) 0)#defineSNDRV_DEV_CONTROL ((__force snd_device_type_t) 1)...
rc = snd_pcm_open(&handle,"default", SND_PCM_STREAM_PLAYBACK,0);if(rc <0) { fprintf(stderr,"unable to open pcm device:%s\n", snd_strerror(rc));exit(1); } /* Alloc a hardware parameters object*/snd_pcm_hw_params_alloca(¶ms);/* Fill it with default values */snd_pcm_hw...
根据声卡的实际能力,驱动实际上可以挂载更多种类的设备,在include/sound/core.h中,定义了以下设备类型,通常更关心的是pcm和control这两种设备,Default 一个声卡对应一个 Control 设备。 #define SNDRV_DEV_TOPLEVEL ((__force snd_device_type_t) 0)
device:pcm设备编号; streams:数组长度为2,元素0指向playback stream设备,元素1指向capture stream设备; private_data:在很多数据结构里面都可以看到,一般用于指向私有数据; 1.1.2 struct snd_pcm_str struct snd_pcm_str用于表示pcm stream,定义在include/sound/pcm.h; ...
20、_mixer_oss *mixer_oss;int mixer_oss_change_count;#endif;/* main structure for soundcard */struct snd_card int number;/* number of soundcard (index to snd_cards) */char id16;char driver16;char shortname32;/* id string of this card */* driver name */* short name of this soun...