[HID][asus] Fn+Esc not handled on ASUS ProArt P16

[HID][asus] Fn+Esc not handled on ASUS ProArt P16

[Massimo Giambona]

Hello,

on ASUS ProArt P16 laptops the Fn+Esc key is not handled by the hid-asus
driver.

When pressing Fn+Esc, dmesg shows:

   [21348.413951] asus 0003:0B05:19B6.0002: Unmapped Asus vendor 
usagepage code 0x4e
   [21348.498405] asus 0003:0B05:19B6.0002: Unmapped Asus vendor 
usagepage code 0x4e

One message is for press, the other for release.

According to USB PCap traces (see 
https://gitlab.com/asus-linux/asusctl/-/issues/585),
Fn+Esc sends:

   - 0x5ad04e01 (enable)
   - 0x5ad04e00 (disable)

It would be useful to map this to KEY_FN_ESC (or another appropriate 
keycode)
in drivers/hid/hid-asus.c so that it becomes available to userspace.

System information:
- Model: ASUS ProArt P16 H7606 (BIOS 319)
- Kernel version: Linux 6.15.10-200.fc42.x86_64
- evtest: no event generated
- dmesg: "Unmapped Asus vendor usagepage code 0x4e"
- Distribution: Fedora 42 Workstation

Additional notes:
- I tested a local modification of hid-asus.c:

     case 0x4e:
         asus_map_key_clear(KEY_FN_ESC);

   With this, Fn+Esc is mapped correctly.
- I also tried sending the raw reports to enable/disable the FnLock feature
   from the driver, but hit an error:
     "BUG: scheduling while atomic"
- I wrote a small tool: https://github.com/m4ss1m0g/proart_p16_fnlock

Could you please consider adding support for this key to the driver?

Thanks for your work,

Massimo

P.S. Other unmapped vendor codes were also observed on this machine:
- Fn+F8  (emoji): dmesg code 0x7e
- Fn+F12 (ProArt): dmesg code 0x8b
- Fn+F10 (Camera toggle): dmesg codes 0x85, 0x01 (but work)
These may also deserve mapping, but Fn+Esc is the most important one.