As a newcomer to alsa, I have a few more probably simple questions. I noticed in the SOC drivers, that when the struct snd_pcm_ops is filled in, .copy is omitted, for example in file s3c24xx-pcm.c, you see the following initialization.

static struct snd_pcm_ops s3c24xx_pcm_ops = { .open = s3c24xx_pcm_open, .close = s3c24xx_pcm_close, .ioctl = snd_pcm_lib_ioctl, .hw_params = s3c24xx_pcm_hw_params, .hw_free = s3c24xx_pcm_hw_free, .prepare = s3c24xx_pcm_prepare, .trigger = s3c24xx_pcm_trigger, .pointer = s3c24xx_pcm_pointer, .mmap = s3c24xx_pcm_mmap, };

How is this supposed to work if somewhere down the line substream->ops->copy is called?

Thanks in advance for any pointers.