Hey, On Tue, 28 Apr 2020, Takashi Iwai wrote: > I believe the missing piece here is a generic way to tell user-space > that the stream got invalidated. This would be useful not only for > aloop but can be applied in general when a stream becomes temporarily > unavailable (e.g. the HDMI monitor disconnected or the DSP route > switched). ack on that. I've been preparing this patch to add -ENODATA to alsa-lib documentation: "[RFC] pcm: add documentation for -ENODATA error code handling" https://github.com/kv2019i/alsa-lib/commit/87b298106e04054489ee93b26a610e37f99a3171 Have not yet had time to send a proper version to the list, but it's addressing specifically this need. This would serve as the interface for SOF DSP to tell that a given PCM node will not be providing data (as the DSP topology is not fully connected) [1]. To test the above, I've used a small hack to aplay/arecord that keeps trying to restart the PCM after a delay, in case -ENODATA is returned: https://github.com/kv2019i/alsa-utils/commit/a2ba541ea0b3e86a65687de88a41f10cf0a8ddc2 [1] https://github.com/thesofproject/sof/issues/2564 Br, Kai
