Fix flickering OSD and refactor logic for volume slider.

[reitermarkus]

This fixes the flickering/hiding of the display's OSD by readding errorRecoveryWaitTime: self.hideOsd ? 0 : nil which was removed.

Also, the volume slider now behaves the same way as the native macOS volume slider: It will only change the volume after a mouse-up event and it will also play the volume-changed sound.

[robertbressi]

This will undo the performance improvements for repeated and held-down media key volume commands made by executing the set volume DDC command on the main thread (per my initial analysis in #134).

[reitermarkus]

Are you saying we should be using DispatchQueue.main instead of DispatchQueue.global(qos: .userInitiated) here?

[robertbressi]

The DDC write command is already being run on the main thread, so you shouldn't need to enclose this in a DispatchQueue block at all, unless you're running the setVolume method from a background thread.

I'm happy to test out this PR and tinker with it as well to see if there's any regression in performance from this change though - my monitor at work has an OSD that behaves in a similar way to yours, but my home one doesn't, so I only have limited opportunities to test.

[reitermarkus]

you shouldn't need to enclose this

Doesn't hurt to be explicit, especially since in this case it is critical where it is run.

I'm happy to test out this PR

Please do.

[JoniVR]

I can confirm this returns the Osd hiding on my display back to previous behaviour.

One problem I noticed during testing:
When I mute and then unmute, volume is not being restored to the previous value (before muting) with these changes.

[reitermarkus]

volume is not being restored to the previous value

You're right, same for me. I'll look into it.

[reitermarkus]

Should be fixed.

[reitermarkus]

Also, @ScorpionDev, I just tried switching from DispatchQueue.global(qos: .userInitiated) to DispatchQueue.main and performance gets worse for me.

[robertbressi]

I've spotted two issues with this build:

1. The "mute" OSD image now comes up intermittently or is completely wrong when toggling mute (see gif below):
   
2. When holding down the volume up key, when the volume gets to maximum, the volume pop sound continues to be played as long as you hold down the key instead of stopping once the volume hits maximum

Performance seems fine with the writes happening on the background thread, from what I can see, anyway.

[jererobles]

Was there any development on this PR? Currently facing the same issue.

[JoniVR]

Closing this as it looks pretty abandoned, feel free to reopen :)