Input lags in Cinnamon

[jfu334]

Cinnamon 4.8.6 
Debian Bullseye
Radeon RX 580 Series (POLARIS10, DRM 3.40.0, 5.10.30, LLVM 11.0.1) (0x67df), amdgpu
Linux 5.10.30

Issue

Brief lags of cinnamon

Steps to reproduce

Most obviously the issue happens when leaving a VMWare Virtual Machine window with captured keyboard+mouse. The whole desktop lags for 0.5..1s.

The effect is also reproducible (but to a lesser extent) when using Kate. The shift key is often misplaced when a completion window has been shown before. It appears as if the actual key press events and the state of the shift key are out of sync.

More detailed description of the effect in Kate:

• When pressing the keys '-', 'hold Shift', '>' the text "_>" appears instead of the expected "->".
• This seems to happen when Kate opens an auto complete window after the keys have been pressed.

These effects do not happen with any other Desktop Environment! They appears in cinnamon only.

Expected behaviour

There shouldn't be any lags

Other information

I'd guess the issue is somehow related to the keyboard layout. Maybe changes in the Xorg keyboard mapping trigger an action within the cinnamon process that blocks for a certain amount of time.

I'd like to do a further investigation but a starting point would be much appreciated. Maybe someone can point me to a location in the source where the keyboard stuff is done.

[ItzSwirlz]

Doesn't VMWare have drivers or something for virtual machines? If so install it and see if that fixes problems. I remember that there are VMWare tools or something. But if it's not having issues on other DE's who knows. Do me a favor and attach your xsession errors file

[jfu334]

You don't understand. This happens on the host, not inside the guest.

Also the issue with kate is not related to virtualization in any way, it just happens with a simple Qt application on an otherwise empty cinnamon desktop. It appears that we have 2 completely different triggers (vmware, kate) for the same issue.

The cinnamon process seems to responds to something (most probably related to keyboard stuff that comes into action when switching X windows) with an action that takes too much time. During this time, the cinnamon process is blocked and with that is the whole desktop.