Bitwig: clap_host::request_restart doesn't trigger deactivate/activate

[LucasThompson]

Bitwig doesn't seem to ever deactivate the plugin after a request to restart. The docs do say that the operation may be delayed by the host, but it seems doubtful that the calls are ever going to come, as stop_processing and start_processing are called in response to the request from the audio thread, perhaps instead of deactivating + activating?

This makes it impossible to reconfigure parameters and notes + audio ports, as the plugin must be in a deactivated state in order to do so (according to the spec). Bitwig does report that it supports all of the audio port rescan flags, which makes it even more unexpected that this restart flow isn't working as detailed in the spec.

REAPER, for example, does call deactivate followed by activate. Why is Bitwig stopping and starting audio processing instead?

Am I missing something?

Enviornment:

• Bitwig Studio 5.0
• CLAP 1.1.8
• macOS 13.4

I've not tried other platforms, but this also occurs with Bitwig Studio 4.4.10

[abique]

Hi @LucasThompson ,

I'm aware of this issue and it is fixed in our development branch, unfortunately this won't be merged into the 5.0 branch as it is part of a larger change/refactoring which came too late and was considered too risky to get merged into 5.0.

Sorry, you'll have to wait a bit for the fix.

Cheers,
Alex

[abique]

Fix is merged for 5.1.

[mccann]

Hi, I'm experiencing this problem even in 5.1, and 5.1.6 -- Also on macOS.

In my situation, I have a plugin that only has a single note port in. (It's a note-analyzer, and I want to change the dialects )
When requesting a restart, nothing happens.

There is however one interesting twist. Bitwig will start to function as expected, if I manually via Bitwig GUI push the device 'off/on' orange-power-button. (Which calls stop_processing, start_processing). Once I've clicked that button, requests to restart DO work.

FYI, I'm calling request from the GUI/Main thread, but the result is the same when I shunted the call over to the audio thread.

My intuition is that the initial state is somehow blocking the functionality, but the "power cycle" somehow triggers a functional state.

[abique]

Hi @mccann ,
Could you give me a build of your plugin and exact steps so I could repro?
Thank you very much 👍

[mccann]

@abique Hello,

Would be a bit troublesome to give you a build, but I have made a minimal plugin that has the same problem here: https://github.com/mccann/CLAP-Restart-Test

It has instructions to reproduce in its README.

It is based on the minimal plugin I made for #58