.pcm_ops = &s3c_dma_ops, .pcm_new = s3c_dma_new, .pcm_free = s3c_dma_free_dma_buffers, }; static struct snd_pcm_ops s3c_dma_ops = { .open = s3c_dma_open, .close = s3c_dma_close, .ioctl = snd_pcm_lib_ioctl, .hw_params = s3c_dma_hw_params, .hw_free = s3c_dma_hw...
==> return snd_pcm_hw_open_fd(pcmp, name, fd, 0, sync_ptr_ioctl); ==> snd_pcm_new(&pcm, SND_PCM_TYPE_HW, name, info.stream, mode); pcm->ops = &snd_pcm_hw_ops; pcm->fast_ops = &snd_pcm_hw_fast_ops; static int snd_pcm_hw_mmap_control(snd_pcm_t *pcm) { snd_pcm...
.pcm_ops = &s3c_dma_ops, .pcm_new = s3c_dma_new, .pcm_free = s3c_dma_free_dma_buffers, }; static struct snd_pcm_ops s3c_dma_ops = { .open = s3c_dma_open, .close = s3c_dma_close, .ioctl = snd_pcm_lib_ioctl, .hw_params = s3c_dma_hw_params, .hw_free = s3c_dma_hw...
阻塞模式下的ALSA 'snd_pcm_writei'行为是指在音频应用程序中使用ALSA库函数'snd_pcm_writei'进行音频数据写入时的一种工作模式。在阻塞模式下,当调用'snd_pcm_writei'函数时,如果音频缓冲区已满,则该函数会阻塞程序的执行,直到有足够的空间来写入音频数据为止。
static struct snd_pcm_ops s3c_dma_ops = { .open = s3c_dma_open, .close = s3c_dma_close, .ioctl = snd_pcm_lib_ioctl, .hw_params = s3c_dma_hw_params, .hw_free = s3c_dma_hw_free, .prepare = s3c_dma_prepare, .trigger = s3c_dma_trigger, ...
.pcm_free = s3c_dma_free_dma_buffers, }; static struct snd_pcm_ops s3c_dma_ops = { .open = s3c_dma_open, .close = s3c_dma_close, .ioctl = snd_pcm_lib_ioctl, .hw_params = s3c_dma_hw_params, .hw_free = s3c_dma_hw_free, ...
iface字段 定义了control的类型,形式为SNDRV_CTL_ELEM_IFACE_XXX,对于mixer是SNDRV_CTL_ELEM_IFACE_MIXER,对于不属于mixer的全局控制,使用CARD;如果关联到某类设备,则是PCM、RAWMIDI、TIMER或SEQUENCER。在这里,我们主要关注mixer。 name字段 是名称标识,这个字段非常重要,因为control的作用由名称来区分,对于名称相同的...
@@ -271,23 +277,12 @@ static int txx9aclc_pcm_close(struct snd_pcm_substream *substream) return 0; }static const struct snd_pcm_ops txx9aclc_pcm_ops = { .open = txx9aclc_pcm_open, .close = txx9aclc_pcm_close, .ioctl = snd_pcm_lib_ioctl, .hw_params = txx9aclc_pcm_...
74 BOOL 1 PCM0 O02 Switch Off 75 ENUM 1 Left PGA Mux OPEN 76 ENUM 1 Right PGA Mux OPEN 77 ENUM 1 AIF TX Mux Digital MIC 78 ENUM 1 HPOUT Mux OPEN 79 ENUM 1 LINEOUT Mux OPEN 80 BOOL 1 DMIC Data Gen Switch Off 81 BOOL 1 AMIC Data Gen Switch Off ...
==> 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...