Issue with custom XKB keymap

[infokiller]

Thanks for this terminal - it's really the best I've seen so far!

As for my issue: I'm running a custom XKB keymap which uses CapsLock as another modifier (ISO_LEVEL5_Shift), and I configured CapsLock+Alt+j to redirect to the Home key. Most applications work fine with that setting, including other terminal emulators I tested. However, Kitty seems to pass different keys to the running application, which I tested by using Ctrl-v in a shell.

Here's the Kitty keyboard debug log I'm seeing:

❯ kitty --debug-keyboard --config /dev/null
Press scancode: 0x42 clean_sym: ISO_Level5_Shift composed_sym: ISO_Level5_Shift mods: none glfw_fallback_key: 280 (CAPS LOCK) xkb_key: 65509 (Caps_Lock)
on_key_input: glfw key: 280 native_code: 0xffe5 action: PRESS mods: 0x0 text: '' state: 0 sent key to child
Press scancode: 0x40 clean_sym: Alt_L composed_sym: Alt_L active_unknown_mods: Mod3 mods: none glfw_key: 342 (LEFT ALT) xkb_key: 65513 (Alt_L)
on_key_input: glfw key: 342 native_code: 0xffe9 action: PRESS mods: 0x0 text: '' state: 0 sent key to child
Press scancode: 0x6e clean_sym: Home composed_sym: Home active_unknown_mods: Mod3 mods: alt glfw_key: 268 (HOME) xkb_key: 65360 (Home)
on_key_input: glfw key: 268 native_code: 0xff50 action: PRESS mods: 0x4 text: '' state: 0 sent key to child
Release scancode: 0x6e clean_sym: Home mods: alt glfw_key: 268 (HOME) xkb_key: 65360 (Home)
on_key_input: glfw key: 268 native_code: 0xff50 action: RELEASE mods: 0x4 text: '' state: 0 ignoring as keyboard mode does not allow release events
Release scancode: 0x40 clean_sym: Alt_L mods: alt glfw_key: 342 (LEFT ALT) xkb_key: 65513 (Alt_L)
on_key_input: glfw key: 342 native_code: 0xffe9 action: RELEASE mods: 0x4 text: '' state: 0 ignoring as keyboard mode does not allow release events
Release scancode: 0x42 clean_sym: ISO_Level5_Shift mods: none glfw_fallback_key: 280 (CAPS LOCK) xkb_key: 65509 (Caps_Lock)
on_key_input: glfw key: 280 native_code: 0xffe5 action: RELEASE mods: 0x0 text: '' state: 0 ignoring as keyboard mode does not allow release events

Looking at the log, I suspect the issue is the PRESS mods: 0x4 part, where Kitty treats the alt mod as pressed. Here's a relevant excerpt from my XKB keymap file:

    key <AC07> {
        type = "EIGHT_LEVEL_ALPHABETIC",
        symbols[Group1] = [ j, J, j, J],
        actions[Group1] = [ NoAction(),  NoAction(), NoAction(), NoAction(), RedirectKey(key =<LEFT>,clearMods =LevelFive), RedirectKey(key =<LEFT>,clearMods =LevelFive), RedirectKey(key =<HOME>,clearMods =Alt+LevelFive),  RedirectKey(key =<HOME>,clearMods =Alt+LevelFive) ],
    };

Running xev -event keyboard shows that the mod is correctly set by XKB:

❯ xev -event keyboard
Outer window is 0x6400001, inner window is 0x6400002

KeymapNotify event, serial 24, synthetic NO, window 0x0,
    keys:  4294967234 0   0   0   16  0   0   0   0   0   0   0   0   0   0   0
           0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0

KeymapNotify event, serial 24, synthetic NO, window 0x0,
    keys:  4294967234 0   0   0   16  0   0   0   0   0   0   0   0   0   0   0
           0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0

KeyRelease event, serial 25, synthetic NO, window 0x6400001,
    root 0x1e4, subw 0x0, time 552656814, (508,983), root:(1364,1015),
    state 0x0, keycode 36 (keysym 0xff0d, Return), same_screen YES,
"   XLookupString gives 1 bytes: (0d) "
    XFilterEvent returns: False

KeyPress event, serial 28, synthetic NO, window 0x6400001,
    root 0x1e4, subw 0x0, time 552661215, (508,983), root:(1364,1015),
    state 0x0, keycode 66 (keysym 0xfe11, ISO_Level5_Shift), same_screen YES,
    XLookupString gives 0 bytes:
    XmbLookupString gives 0 bytes:
    XFilterEvent returns: False

KeyPress event, serial 28, synthetic NO, window 0x6400001,
    root 0x1e4, subw 0x0, time 552661215, (508,983), root:(1364,1015),
    state 0x20, keycode 64 (keysym 0xffe9, Alt_L), same_screen YES,
    XLookupString gives 0 bytes:
    XmbLookupString gives 0 bytes:
    XFilterEvent returns: False

KeyPress event, serial 28, synthetic NO, window 0x6400001,
    root 0x1e4, subw 0x0, time 552661607, (508,983), root:(1364,1015),
    state 0x0, keycode 110 (keysym 0xff50, Home), same_screen YES,
    XLookupString gives 0 bytes:
    XmbLookupString gives 0 bytes:
    XFilterEvent returns: False

KeyRelease event, serial 28, synthetic NO, window 0x6400001,
    root 0x1e4, subw 0x0, time 552661678, (508,983), root:(1364,1015),
    state 0x0, keycode 110 (keysym 0xff50, Home), same_screen YES,
    XLookupString gives 0 bytes:
    XFilterEvent returns: False

KeyRelease event, serial 28, synthetic NO, window 0x6400001,
    root 0x1e4, subw 0x0, time 552662102, (508,983), root:(1364,1015),
    state 0x28, keycode 64 (keysym 0xffe9, Alt_L), same_screen YES,
    XLookupString gives 0 bytes:
    XFilterEvent returns: False

KeyRelease event, serial 28, synthetic NO, window 0x6400001,
    root 0x1e4, subw 0x0, time 552662103, (508,983), root:(1364,1015),
    state 0x20, keycode 66 (keysym 0xfe11, ISO_Level5_Shift), same_screen YES,
    XLookupString gives 0 bytes:

Specifically, see this part from that log:

KeyPress event, serial 28, synthetic NO, window 0x6400001,
    root 0x1e4, subw 0x0, time 552661607, (508,983), root:(1364,1015),
    state 0x0, keycode 110 (keysym 0xff50, Home), same_screen YES,
    XLookupString gives 0 bytes:
    XmbLookupString gives 0 bytes:
    XFilterEvent returns: False

As you can see in the bolded part, the state of the modifiers is set to 0x0, which means no modifiers should be active.

[bew]

I think this will be resolved with the solution to #1980 (WIP)

[bew]

See also #2000

[infokiller]

@bew reading #2000 I understand that your proposed fix is to handle non-standard modifiers (I use ISO_Level5_Shift specifically here). But isn't the issue here that the Alt modifier is detected even though XKB cleared it?

[bew]

But isn't the issue here that the Alt modifier is detected even though XKB cleared it?

Yes, but in general kitty currently does not remove consumed mods (the non-standard mod and alt) for a key event, which is part of what I want to fix too

[rien333]

This is very similar to my problem: #1255. Due to the fact that glfw (kitty's backend) only recognizes a very small subset of modifiers, any modifiers outside of this small set behave oddly (see the discussion over at the glfw repo). In my case, my custom (caps-lock based) modifier causes kitty to scroll down fully (as if you pressed an actual key). This can become very annoying, as I use this custom modifier to switch windows.

Can you confirm that kitty also scrolls down when you press your (custom) modifier, @infokiller? If so, I hypothesize that any 'glwf fallback key' causes kitty to scroll down, which might fixable on kitty's side.

[infokiller]

@rien333 in my case it doesn't scroll down

[evelineraine]

I have a similar issue with my custom XKB layout - I have ^ moved to QWERTY 8 (shiftless). When I press Ctrl-^ (keybinding used in Vim), I have one character deleted in the shell (like Backspace does), and nothing happening in Vim.

From the --debug-keyboard output I assume that GLFW doesn't recognize what key is being pressed, and falls back to treating it as 8, and then sends Ctrl-8 to the shell (which seems to erase one character left, for some reason).

Press xkb_keycode: 0x64 clean_sym: Control_R composed_sym: Control_R mods: none glfw_key: 345 (RIGHT CONTROL) xkb_key: 65508 (Control_R)
on_key_input: glfw key: 345 native_code: 0xffe4 action: PRESS mods: 0x0 text: '' state: 0 sent key to child
Press xkb_keycode: 0x9 clean_sym: asciicircum composed_sym: asciicircum mods: ctrl glfw_fallback_key: 56 (8) xkb_key: 56 (8)
on_key_input: glfw key: 56 native_code: 0x38 action: PRESS mods: 0x2 text: '' state: 0 sent key to child
Release xkb_keycode: 0x9 clean_sym: asciicircum mods: ctrl glfw_fallback_key: 56 (8) xkb_key: 56 (8)
on_key_input: glfw key: 56 native_code: 0x38 action: RELEASE mods: 0x2 text: '' state: 0 ignoring as keyboard mode does not allow release events
Release xkb_keycode: 0x64 clean_sym: Control_R mods: ctrl glfw_key: 345 (RIGHT CONTROL) xkb_key: 65508 (Control_R)
on_key_input: glfw key: 345 native_code: 0xffe4 action: RELEASE mods: 0x2 text: '' state: 0 ignoring as keyboard mode does not allow release events

So, GLFW causes issues even with standard modifier - Ctrl.

I wish I could use something like Keyboardio's key layout util to shuffle the keys at firmware level and make everything appear standard QWERTY to the OS - but my laptop's keyboard is not programmable, so I have to use custom xkb layouts.

And I'm afraid until this issue is fixed, Kitty is a no-go for me 😞

[Luflosi]

I'll add the ^ key tomorrow, that will hopefully fix your problem.

[Luflosi]

@evelineraine please test if #2222 fixes your problem.

[evelineraine]

@Luflosi I have build kitty from #2222 and it still doesn't work. I see that glfw recognises the key now, but still Vim doesn't receive Ctrl-^ correctly and nothing happens.

Press xkb_keycode: 0x64 clean_sym: Control_R composed_sym: Control_R mods: none glfw_key: 345 (RIGHT CONTROL) xkb_key: 65508 (Control_R)
on_key_input: glfw key: 345 native_code: 0xffe4 action: PRESS mods: 0x0 text: '' state: 0 sent key to child
Press xkb_keycode: 0x9 clean_sym: asciicircum composed_sym: asciicircum mods: ctrl glfw_key: 94 (CIRCUMFLEX) xkb_key: 94 (asciicircum)
on_key_input: glfw key: 94 native_code: 0x5e action: PRESS mods: 0x2 text: '' state: 0 sent key to child
Release xkb_keycode: 0x9 clean_sym: asciicircum mods: ctrl glfw_key: 94 (CIRCUMFLEX) xkb_key: 94 (asciicircum)
on_key_input: glfw key: 94 native_code: 0x5e action: RELEASE mods: 0x2 text: '' state: 0 ignoring as keyboard mode does not allow release events
Release xkb_keycode: 0x64 clean_sym: Control_R mods: ctrl glfw_key: 345 (RIGHT CONTROL) xkb_key: 65508 (Control_R)
on_key_input: glfw key: 345 native_code: 0xffe4 action: RELEASE mods: 0x2 text: '' state: 0 ignoring as keyboard mode does not allow release events

[Luflosi]

@kovidgoyal do you know why this doesn't work?

[kovidgoyal]

You will need to add it to control_codes in keys.py. I am guessing OP
wants it to generate the same code as ctrl+6, so add it next to line 130

[Luflosi]

diff --git a/kitty/keys.py b/kitty/keys.py
index 5d6e92c6..9184a1be 100644
--- a/kitty/keys.py
+++ b/kitty/keys.py
@@ -128,6 +128,7 @@ control_codes[defines.GLFW_KEY_3] = (27,)
 control_codes[defines.GLFW_KEY_4] = (28,)
 control_codes[defines.GLFW_KEY_5] = (29,)
 control_codes[defines.GLFW_KEY_6] = (30,)
+control_codes[defines.GLFW_KEY_CIRCUMFLEX] = (30,)
 control_codes[defines.GLFW_KEY_7] = (31,)
 control_codes[defines.GLFW_KEY_SLASH] = (31,)
 control_codes[defines.GLFW_KEY_8] = (127,)

@kovidgoyal Like this?

I am guessing OP wants it to generate the same code as ctrl+6

@evelineraine Is that correct? If so, try building with the patch applied.

[kovidgoyal]

yes, like that