On 2022-11-11 17:06, Josh Triplett wrote:
I have an external ThinkPad USB keyboard: $ lsusb | grep -i keyboard Bus 003 Device 022: ID 17ef:6047 Lenovo ThinkPad Compact Keyboard with TrackPointThe Linux kernel exposes a fn_lock attribute in sysfs for this keyboard:$ cat sys/devices/pci0000:00/0000:00:14.0/usb3/3-5/3-5.4/3-5.4.3/3-5.4.3:1.1/0003:17EF:6047.000F/fn_lock 1 However, this attribute appears inverted for this particular keyboard: it seems to be 1 when FnLock is *disabled* and 0 when FnLock is *enabled*. In order to enable FnLock, I have to write 0 to this file.
Under Windows the default actions of the Function keys are the media keys, i.e. pressing F1 is Mute. Fn-"Mute" is F1, or enabling Fn-Lock & "Mute". That's why when /fn_lock is 1, the Mute key is F1.
With keyboards built into Thinkpads there's a BIOS setting to invert the behaviour of Fn-Lock (and thus have Fn keys by default), as well as swapping Fn<->Ctrl, but there's no equivalent option for the external keyboards.
What's the wrong way around here is hid-lenovo assumes that you want Fn-Lock on when connecting to the keyboard, not off. My assumption at the time was that whilst it's different to how the keyboard behaves under Windows, it'd be a more useful default.
(Also, separately from that, it would be nice if the kernel could handle fn_lock toggling *internally*, rather than expecting userspace to do it.As far as I can tell, it does handle similar things for some keyboards, but not this one.)
Agreed. This was something I looked into when I was adding support for the keyboards. For yours it's a pretty trivial addition, but for the USB variant you can't send the command in the middle of the USB interrupt receiving the keypress, solving this seemed to require quite a lot of boilerplate for what would have been pretty trivial in userland.
Of course, It's very easily possible that I missed something, or there's a helper to do this sort of thing that now exists.
Cheers,