Special keys on Dell XPS L502X

[My Th]

Hi!

I have Dell XPS L502X laptop and it has three special keys, but they are
not working out-of-the-box. I wanted to assign functions to them (e.g.
toogle LCD backlight) so I used xev to look for their keycodes as
described at http://linux.oneandoneis2.org/keys.htm

But these special keys behave differently than the normal keys on the
keyboard, so I don't know how could I configure them to do the task I
want. Is this behavior a bug? For details see below.

Key 1:
------

FocusOut event, serial 37, synthetic NO, window 0x3c00001,
    mode NotifyGrab, detail NotifyAncestor

FocusOut event, serial 37, synthetic NO, window 0x3c00001,
    mode NotifyUngrab, detail NotifyPointer

FocusIn event, serial 37, synthetic NO, window 0x3c00001,
    mode NotifyUngrab, detail NotifyAncestor

KeymapNotify event, serial 37, synthetic NO, window 0x0,
    keys:  4294967212 0   0   0   0   0   32  0   0   0   0   0   0   0
0   0   
           32  0   0   0   0   0   0   0   0   0   0   0   0   0   0
0   

KeyPress event, serial 37, synthetic NO, window 0x3c00001,
    root 0xac, subw 0x0, time 272973623, (152,98), root:(154,170),
    state 0x2040, keycode 53 (keysym 0x78, x), same_screen YES,
    XLookupString gives 1 bytes: (78) "x"
    XmbLookupString gives 1 bytes: (78) "x"
    XFilterEvent returns: False

KeyRelease event, serial 37, synthetic NO, window 0x3c00001,
    root 0xac, subw 0x0, time 272973625, (152,98), root:(154,170),
    state 0x2040, keycode 53 (keysym 0x78, x), same_screen YES,
    XLookupString gives 1 bytes: (78) "x"
    XFilterEvent returns: False

KeyRelease event, serial 37, synthetic NO, window 0x3c00001,
    root 0xac, subw 0x0, time 272973629, (152,98), root:(154,170),
    state 0x2040, keycode 133 (keysym 0xffeb, Super_L), same_screen YES,
    XLookupString gives 0 bytes: 
    XFilterEvent returns: False

Basically this just writes "x" in the terminal, but it generates extra
events.


Key 2:
------

FocusOut event, serial 37, synthetic NO, window 0x3c00001,
    mode NotifyGrab, detail NotifyAncestor

FocusOut event, serial 37, synthetic NO, window 0x3c00001,
    mode NotifyUngrab, detail NotifyPointer

FocusIn event, serial 37, synthetic NO, window 0x3c00001,
    mode NotifyUngrab, detail NotifyAncestor

KeymapNotify event, serial 37, synthetic NO, window 0x0,
    keys:  2   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   0   0   0
0   

RRNotify event, serial 37, synthetic NO, window 0x3c00001,
    subtype XRROutputPropertyChangeNotifyEvent
    output LVDS1, property BACKLIGHT, timestamp 272980484, state
NewValue

This decreases display brightness.


Key 3:
-----

FocusOut event, serial 40, synthetic NO, window 0x3c00001,
    mode NotifyGrab, detail NotifyAncestor

FocusOut event, serial 40, synthetic NO, window 0x3c00001,
    mode NotifyUngrab, detail NotifyPointer

FocusIn event, serial 40, synthetic NO, window 0x3c00001,
    mode NotifyUngrab, detail NotifyAncestor

KeymapNotify event, serial 40, synthetic NO, window 0x0,
    keys:  2   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   0   0   0
0   

This one seems to do nothing.

I'm using Gentoo Linux
x11-base/xorg-server 1.11.4
3.2.9-gentoo #1 SMP PREEMPT x86_64 Intel(R) Core(TM) i7-2630QM CPU

Any advice would be appreciated.


Reinis