On Mon, Jul 03, 2023 at 02:07:10PM +0200, Takashi Iwai wrote:
Shengjiu Wang wrote:
There is no such memory to memory interface defined in ALSA. Seems ALSA is not designed for M2M cases.
There is no restriction to implement memory-to-memory capture in ALSA framework. It'd be a matter of the setup of PCM capture source, and you can create a corresponding kcontrol element to switch the mode or assign a dedicated PCM substream, for example. It's just that there was little demand for that.
Yeah, it's not a terrible idea. We might use it more if we ever get better support for DSP audio, routing between the DSP and external devices if driven from the CPU would be a memory to memory thing.
I'm not much against adding the audio capture feature to V4L2, though, if it really makes sense. But creating a crafted /dev/audio* doesn't look like a great idea to me, at least.
I've still not looked at the code at all.