Diagnose why external monitor not sleeping

[hyperknot]

Hi,

Since a day or two, my external monitor doesn't go to sleep. How can I diagnose what is causing it to keep on? I've restarted the computer a few times, M1 Macbook Pro 16.

 

[BrianBaughn]

What model monitor?

 

[hyperknot]

It's a normal Asus PA279CV, nothing special, over USB-C. It used to sleep perfectly.

 

[hyperknot]

I think it must be AlDente, which disables sleep on the computer while charging, but I'm surprised it does the same on the display as well.

 

[BrianBaughn]

Do you have any devices connected to the USB hub on the monitor?

 

[hyperknot]

Nothing connected. It's definitely AlDente. It freezes if I click on it, and then after about a minute, it turns the display off. BTW, not even the screensaver starts.

 

[hyperknot]

Yes, I confirmed it's a bug in AlDente.

 

[BrianBaughn]

That monitor has a history of the problem, though…and not just in macOS.

 

[hyperknot]

Mine has been perfect. I had loads of problems with a Dell and then upgraded to this. I started with a FW update but it's been flawless ever since.