linux: Send scancode instead of keycodes

[rofferom]

X11 sends Linux keycodes that only match scancodes on a limited
part of the keys. For example for extended scancodes, the values
don't match.

showkey command can display a mapping:

• https://linux.die.net/man/1/showkey

• https://github.com/legionus/kbd/blob/master/src/showkey.c

• Tested on all platforms changed

• Added an entry to CHANGELOG.md if knowledge of this change could be valuable to users

• Updated documentation to reflect any user-facing changes, including notes of platform-specific behavior

• Created or updated an example program if it would help users understand this functionality

• Updated feature matrix, if new features were added or implemented

[maroider]

Thanks for taking the time to contribute (and apologies for taking so long to respond). Is this supposed to map Linux's keycodes to USB HID scancodes?

[rofferom]

Yes it is, but actually all implementations send "OS keycodes" rather than the raw HID scancode. My patch is incomplete, I'm not event using it anymore. Furthermore, it is a breaking change.

Maybe the correct fix would be to update the documentation of winit::event::ScanCode, because the values are more "OS/Hardware-dependent keyboard scan code".

What do you think about that ?

[maroider]

What do you think about that?

Welp, I kind of forgot to reply before now. Basically, I think #2662 is preferable, since it would give you a proper platform-independent value instead of passing through the platform-dependent "scancode/keycode".

[kchibisov]

Thanks for your patch, but as it was stated and as it was there for years I think, the keyboard API model proposed in #2662 (the patch is new, but the PRs doing it for dedicated platforms did dated since 2020/21) took care of it.