Hi,

I'm an (un)happy user of Asus M50SV notebook.
I have same problems with Fn stuff...
For me works ootb wifi/BT F2, Sleep F1, brightness F5+F6(ambient light sensor must be disabled in win first), LCD on/off F7, on LCD/VGA switch F8 i got instant reboot and the rest of Fn/Buttons are not workimg.
I tried Pentiumpc kext(pkg) but does nothing and IMO is normal since i dont have ASUS010 in my DSDT, instead i have ATK0100 under ATKD device. I modded the kext plist to match mne still no luck.

I found a great app for win only(sad) ASUS Notebook Keys that allows you to remap Media and Fn keys, so I was able to catch those events for not working Media Buttons and Fn keys, also the SOURCE is available maybe in combination with this ACPID - acpi event daemon (for linux if someone can port it for osx) we can get them working as it should...
Multimedia trackpad functions/actions still cant be catched even with this app that make me think is covered only by Synaptys driver, still a weird thing if i set on win trackpad always on multimedia mode(when external mouse is detected) light remain open on trackpad even on OS X but dosent turn off when i take out the external mouse, somehow that driver function set up an ACPI flag... I must investigate this more.

Here is the list of captured events:

Media player arrows keys, dosen't work:
Fn +"":
->: Event: 0x41 - Fast forward
<-: Event: 0x40 - Rewind
^ : Event: 0x43 - Stop
v : Event: 0x45 - Play/Pause

Functions (Fn + F1-F12):
Fn +"":

F1: Event: works - Can't capture it since it goes to sleep
F2: Event: 0x5D works - WiFi/BTt switch
F3: Event: 0x50 - Mail App
F4: Event: 0x51 - Launch browser
F5: Event: 0x2D works - Brightness control down
F6: Event: 0x1E works - Brightness control up
F7: Event: 0x34 works - LCD on/off
F8: Event: 0x61 - LCD/VGA switch(I got instant restart when I use it)
F9: Event: 0x68 - Unknown
F10: Event: 0x32 - Mute
F11: Event: 0x31 - Volume down
F12: Event: 0x30 - Volume up

Keyboard keys that dosent work (+Fn):
Fn +"":
T: Event: 0x99 - Modem on/off
A: Event: 0x7A - Ambient light sensor
C: Event: 0x8A - Unknown
V: Event: 0x82 - Screen capture(I guess)
Space: Event: 0x5C - Launch Power4Gear

Media button key:
Button 1: Event: 0x5C - same function as Fn+Space=Launch Power4Gear
Button 2: Event: 0x6B - Unknown
Button 3: Event: 0x5C - Unknown
Button 4: Event: 0x95 - Unknown
So any idea on how can I fix the remaining Fn that dosen't work?