Dell Precision 7510 (Function key Brightness not working)

Hi,

I' trying to get brightness adjustment working using the keyboard function key but it does not work. I'm seeing the widget appearing, level is changing but brightness not.

My BIOS information

BIOS Information
Vendor: Dell Inc.
Version: 1.14.4
Release Date: 07/28/2017

Kernel version

4.14.5-1-ARCH

The ACPI Kernel error (journalctl -f) + playing with function brightness keys gave me

Dec 18 21:52:55 laptop kernel: ACPI Error: [LCD_] Namespace lookup failure, AE_NOT_FOUND (20170728/psargs-364)
Dec 18 21:52:55 laptop kernel: ACPI Error: Method parse/execution failed \_SB.PCI0.PEG0.PEGP.BRT6, AE_NOT_FOUND (20170728/psparse-550)
Dec 18 21:52:55 laptop kernel: ACPI Error: Method parse/execution failed \EV5, AE_NOT_FOUND (20170728/psparse-550)
Dec 18 21:52:55 laptop kernel: ACPI Error: Method parse/execution failed \SMEE, AE_NOT_FOUND (20170728/psparse-550)
Dec 18 21:52:55 laptop kernel: ACPI Error: Method parse/execution failed \SMIE, AE_NOT_FOUND (20170728/psparse-550)
Dec 18 21:52:55 laptop kernel: ACPI Error: Method parse/execution failed \NEVT, AE_NOT_FOUND (20170728/psparse-550)
Dec 18 21:52:55 laptop kernel: ACPI Error: Method parse/execution failed \_SB.PCI0.LPCB.ECDV._Q66, AE_NOT_FOUND (20170728/psparse-550)

Could it be missing implementation in BIOS of ACPI function/event related to this keys ?

Best regards,
Martin