# Backlight hotkeys not working

## shimitar

Hi!

i have a new Asus Zenbook UX305, a pretty nice ultrabook with an intel video card (broadwell-u).

I can control backlight with xbacklight or, generically, via /sys/class/backlight. But the two dedicated function keys (FN+F5 and FN+F6) do not work.

I have checked with xev, the F5 and F6 keys works, but if i press FN+F5/F6 absolutely NO event is generated.

I tried to add come conbinations of:

```

acpi_osi= acpi_backlight=intel"

pcie_aspm=force acpi_osi=linux acpi_backlight=vendor"

acpi_backlight=vendor acpi_osi=

```

and similar, but with absolutely no luck. All the "function" keys works (even sleep!), but not the two brightness keys.

Does anybody have any idea?

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## DONAHUE

If you don't already have these you might try compiling a kernel with the following menuconfig items:

 *Quote:*   

> Device Drivers  --->
> 
> [*] X86 Platform Specific Device Drivers  --->
> 
> <M>   Asus Laptop Extras
> ...

 

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## shimitar

I actually did not had these drivers loaded, but even if i recompiled, they don't help.

Th asus laptop module does not even load (no such device).

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## DONAHUE

might google 'asus laptop forum' See if you can find a linux Asus Zenbook UX305 user with an answer

might see if the keys work in ubuntu or redhat and if they do see what they use

https://wiki.archlinux.org/index.php/extra_keyboard_keys#Asus_M_series

https://wiki.gentoo.org/wiki/Keyboard_layout_switching

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## shimitar

I did some research and found a few answers, but none for this model. No solution would work for me.

My best guess at the moment is that for some reason the brightness function keys are wired trough ACPI in some ways, and the kernel is not picking them up. This is because those keys does not give any feedback trough the input layer nor the ACPI events layer. 

An intermediate solution, since the backlight works, i will probably map ALT+F5/F6 to xbacklight, which is not idea but quite effective. Then will try again with a newer kernel, maybe a 4.4.0.

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