Arch Linux

bmansurov

Member

Registered: 2016-09-25

Posts: 10

"Control + Right Alt + b" isn't working

I have swapped left Control with left Alt, and disabled right Alt as level 3 chooser like so:

Section "InputClass"
	Identifier "keyboard defaults"
	MatchIsKeyboard "on"

        Option "XKbOptions" "lv3:ralt_alt,ctrl:swap_lalt_lctl"
EndSection

These changes put Control to the left of Space, and Alt to the right of Space, which is convenient for Emacs, for example. I'll refer to this right Alt below as Alt.

In Emacs, hitting Control+Alt+u works. For example, in paredit mode, it executes `paredit-backward-up`. However, Control+Alt+b isn't even recognized. In Emacs it does nothing. Emacs' describe key (C-h k) doesn't capture it, nor does paredit execute `paredit-backward`.

I thought it was because of i3, but I ran Emacs in TTY and had the same problem.

Why is this happening? I suppose the system is capturing this key combination. Is that true? Can you help me debug the issue? Thanks.

Additional info:

[user@laptop ~]$ setxkbmap -query
rules:      evdev
model:      pc105
layout:     us
options:    lv3:ralt_alt,ctrl:swap_lalt_lctl

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 78,697

Re: "Control + Right Alt + b" isn't working

Does the combo generate any event?
Eg. w/ "libinput debug-events", showkey (console) or xev (X11)?

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bmansurov

Member

Registered: 2016-09-25

Posts: 10

Re: "Control + Right Alt + b" isn't working

Does the combo generate any event?
Eg. w/ "libinput debug-events", showkey (console) or xev (X11)?

It doesn't look like so. When I run "libinput debug-events" and hold down left Control, right Alt and press B nothing is printed. But when I hold down left Control, left Alt, and press B I see this:

^[^B event4   KEYBOARD_KEY     +41.02s	*** (-1) released
 event4   KEYBOARD_KEY     +45.88s	*** (-1) pressed

A similar thing happens with "xev" and "showkey" — no output using right Alt, but some output using left Alt.

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 78,697

Re: "Control + Right Alt + b" isn't working

You could check the journal for unhandled ACPI events, but what's unfortunately more likely in this setup is that the keyboard isn't completely wired for 3-key events, ie. not all 3-key presses generate an electric signal, esp. since the disfunctional modifier seems to be the original 3rd level shift (AltGr)?

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bmansurov

Member

Registered: 2016-09-25

Posts: 10

Re: "Control + Right Alt + b" isn't working

I tried running `acpi_listen` and then pressing the combo, nothing happened. Other buttons such as volume up output something.

esp. since the disfunctional modifier seems to be the original 3rd level shift (AltGr)?

Not sure. How do I find this out?

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 78,697

Re: "Control + Right Alt + b" isn't working

What does the print say? ;-)
Otherwise figure the keycode (showkey on the console, iirc. AltGr is 100)

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How to upload text · How to boot w/o GUI · Disable Windows Fast-Start! · Fix your xinitrc

bmansurov

Member

Registered: 2016-09-25

Posts: 10

Re: "Control + Right Alt + b" isn't working

The print says "Alt" only. `showkey` says 100.

Thanks for your help, seth!