I was trying out a new usb keyboard and noticed that when I type on multiple usb keyboards simultaneously that the x server will stutter/pause.
For example, typing 1 on one keyboard and typing 1 on the other keyboard causes the x server to pause for a second or more.
Typing 1234 1234 1234 on both keyboards simultaneously causes the x server to pause for a bit longer.
To see the effect, launch something that updates the screen continuously, like VLC or System Monitor (with its running graph), type on both keyboards simultaneously and watch it stutter. (Video playing in VLC stutters, but the sound continues without problem.)
I tried the same thing on knoppix 9.1 (based on debian) and it didn't exhibit the same pausing behavior.
(I also got a new keyboard that has n-key rollover which means that you can have more than 6 keys pressed. It uses a second keyboard input device and sends additional keystrokes to the second device, and this will also trigger the pausing. I hold down 6 keys like keypad 1 through 6, then tapping keypad 7 and 8 quickly will cause the stutter. Also you can mash the entire keypad 1-9 and that will stutter.)
(running 22.04.1 with xorg(x11) server)
Description: Ubuntu 22.04.1 LTS
Doing some more looking, appears to be an "old bug":
Using 2 keyboards at the same time create annoying input lag
Input delay when using two keyboards under Ubuntu 18.04 (Xorg)
