Suppose, you have a computer, which does not have any specific nonstandard settings (such as multiseat).

If two or more keyboards are attached to the same machine (laptop with ext keyboard is common usecase), while the input is focused on a text entry (browser text area on a forum, text editor, terminal emulator or TTY), and you press one of keys which normally both change input mode and have a LED, indicating the current input mode, such as: Caps Lock, Num Lock, Scroll Lock (and others on exotic keyboards), then what will the system do:

a) Input mode is changed for all keyboards, LED is toggled for all keyboards simultaneously.
b) Input mode and LED state are changed only for keyboard, where key is pressed, other keyboard retain their respective input mode and LED states
c) Input mode is changed for all keyboards, however LED is toggled only on the keyboard, where the key was pressed.

Obviously, a and b are sane behaviors, since the input mode is always consistent with LED state, indicating the current input mode. However c is an erroneous behavior, since LED might indicate different input mode to what is actually active (for example, when you type, you get ALL CAPS, but CapsLed is off, or vice versa).

So, I was wondering, is there an option to select between a and b possibilities for Linux-based system?

I have not tried this on other operating systems yet. So can you tell me how they behave, if you have time and resources to test?

inxi --b please

3 post/ Linux newb.? Type that in the terminal "app"


Copy and paste it in a reply.
oug@sparky6:~$ inxi --b
System:
Host: sparky6 Kernel: 5.10.12-sparky-amd64 x86_64
bits: 64 Desktop: LXQt 0.16.1
Distro: SparkyLinux 6 (Po-Tolo)
Machine:
Type: Desktop Mobo: ASUSTeK model: PRIME A320M-K
v: Rev X.0x serial: <superuser required>
UEFI [Legacy]: American Megatrends v: 5408
date: 12/27/2019
CPU:
Info: Quad Core AMD Ryzen 3 3200G with Radeon
Vega Graphics [MCP]
speed: 1396 MHz min/max: 1400/3600 MHz
Graphics:
Device-1: AMD Picasso driver: amdgpu v: kernel
Display: x11 server: X.Org 1.20.10 driver:
loaded: amdgpu,ati
unloaded: fbdev,modesetting,vesa
resolution: 1366x768~60Hz
OpenGL: renderer: AMD Radeon Vega 8 Graphics
(RAVEN DRM 3.40.0 5.10.12-sparky-amd64 LLVM
11.0.1)
v: 4.6 Mesa 20.3.4
Network:
Device-1: Realtek RTL8111/8168/8411 PCI Express
Gigabit Ethernet
driver: r8169
Drives:
Local Storage: total: 223.58 GiB
used: 174.02 GiB (77.8%)
Info:
Processes: 226 Uptime: 14h 06m Memory: 5.75 GiB
used: 2.4 GiB (41.8%) Shell: Bash inxi: 3.3.00
doug@sparky6:~$

> inxi --b please

Sorry, but my question is not specific to any particular machine or GNU/Linux distribution, or even CPU ISA.
I have multiple machines, some are ARM, some i386, some amd64 and some are aarch64.

Though I am primarily thinking about X.org, I would like to receive answers regarding plain TTY, Wayland, and other non-linux OSes as well.

On Fedora 34/KDE in Xorg, with PS/2 keyboard and USB keyboard on ordinary Intel 64bit PC, both keyboards stay totally synchronized.

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