[IDEA] Automatically suspend USB DACs when idle

[arczar]

(probably this reported issue should have been the subject of a new thread)

@arczar ...it may be that your XMOS DIYINHK DAC needs to be powered on (and possibly 'ready') before the RPi so it gets recognised.

No, because before the update it always worked ...

[Tim Curtis]

Test with a fresh image.

[sll552]

I have had time to test if an alsa plugin would work and put something together that I guess could either work or at least be a starting point for having an universal start/stop hook. I would appreciate if someone with a little more knowledge of alsa could take a look at https://github.com/sll552/alsa-shim
I have tested it and it works for my usecase, maybe someone with a more advanced setup could test it too (Spotify, BT, ...).

If I understand correctly moode is already using a customized version of the camillaDSP alsa plugin, so would it possible to add something like this to moode? Only minimal changes should be required to the alsa config.

[Tim Curtis]

I have had time to test if an alsa plugin would work and put something together that I guess could either work or at least be a starting point for having an universal start/stop hook. I would appreciate if someone with a little more knowledge of alsa could take a look at https://github.com/sll552/alsa-shim
I have tested it and it works for my usecase, maybe someone with a more advanced setup could test it too (Spotify, BT, ...).

If I understand correctly moode is already using a customized version of the camillaDSP alsa plugin, so would it possible to add something like this to moode? Only minimal changes should be required to the alsa config.

Looking at the Git repo there is no description of what the code does or examples of how it is to be used.

The other question is why did you choose the Apache 2 License and not GPLv3 or MIT? The ASF states that its compatible with GPLv3 but then I need a Lawyer to understand the rest of their article...
https://www.apache.org/licenses/GPL-compatibility.html

For whatever License you choose, you should add a comment header to the source code that contains a summary statement of the License.

[sll552]

Sorry if it came across as finished. It was not meant to be final, more like a proof of concept. I don't really care about the license so whatever works for you is OK for me.

[sll552]

I changed the License to MIT and added a config example.

[arczar]

Test with a fresh image.

unfortunately, it didn't help. The new version did not change anything either.

[Tim Curtis]

Test with a fresh image.

unfortunately, it didn't help. The new version did not change anything either.

The change in behavior with your particular USB interface could be due to changes in the Linux kernel USB subsystem or the USB audio driver in the 5.15 kernel branch which moOde 8 uses.

USB compatibility issues need to be reported to the kernel maintainers by someone that has that exact hardware and are able to provide steps to reproduce the issue and additional information the kernel devs require.