maintainer-feedback requested: [Bug 278477] x11-servers/xorg-server regression (?) - hardware brightness adjustment blocked in X (T400)

Bugzilla Automation <bugzilla@FreeBSD.org> has asked freebsd-x11 (Nobody)
<x11@FreeBSD.org> for maintainer-feedback:
Bug 278477: x11-servers/xorg-server regression (?) - hardware brightness
adjustment blocked in X (T400)
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=278477



--- Description ---
1/ T400 has Fn key which performs special actions in combination with normal
keys, it does not depend on OS.

2/ The problematic combination is Fn + Home or End for brightness adjustment.
Now, as soon as i915kms.ko is loaded for vt, the combination stops working.
Other combinations still do (e.g. LED light). 

3/ If I do not load X/i915kms.ko or during booting the brightness adjustment
combination works as usual.

4/ I've tried rolling back xorg-server to 1.20.4 but nothing changed. Still,
its somewhat connected with either loading X or i915kms.ko.

5/ Fn + key  do not five separate xev outputs so they are intercepted (?),
similarly to LED light combination.

Fn is -

KeyPress event, serial 32, synthetic NO, window 0x1400001,
    root 0x1d8, subw 0x0, time 38140302, (159,147), root:(551,548),
    state 0x0, keycode 151 (keysym 0x1008ff2b, XF86WakeUp), same_screen YES,
    XLookupString gives 0 bytes: 
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: False

KeyRelease event, serial 32, synthetic NO, window 0x1400001,
    root 0x1d8, subw 0x0, time 38140314, (159,147), root:(551,548),
    state 0x0, keycode 151 (keysym 0x1008ff2b, XF86WakeUp), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False