Bios for DN2820FYK is not exposing ACPI methos for backlight control under Linux

[ddamo11]

Hi,

I have a nuc DN2820FYK running GNU/Linux, it mostly works fine except for the graphics card, I never was able to control the brigthness, it is running always to maximun brightness and it is burning my eyes so this time I did some debugging following this page: https://wiki.ubuntu.com/Kernel/Debugging/Backlight# Into_the_abyss:_looking_at_the_ACPI_BIOS Kernel/Debugging/Backlight - Ubuntu Wiki and indeed it seems the bios (I'm running the lastest version - 059) is not exposing the ACPI methods for backlight control (_BCL, _BCM, _BCQ). Since writing ACPI methods is out of my reach I would like to known if some community member can help me in some way.

this is that I have tried:

first I boot the operating system with kernel parameters as recommend by https://wiki.archlinux.org/index.php/backlight# Kernel_command-line_options https://wiki.archlinux.org/index.php/backlight# Kernel_command-line_options , but no matter what parameters I use it never works, using any combination of acpi_backlight and acpi_osi results in not backlight controls:

nuc ~ # ls -l /sys/class/backlight/

total 0

nuc ~ # acpidump -o acpidump.txt

nuc ~ # acpixtract acpidump.txt

Intel ACPI Component Architecture

ACPI Binary Table Extraction Utility version 20160729-64

Copyright (c) 2000 - 2016 Intel Corporation

Acpi table [DSDT] - 46249 bytes written to dsdt.dat

Acpi table [SSDT] - 1891 bytes written to ssdt1.dat

Acpi table [SSDT] - 656 bytes written to ssdt2.dat

Acpi table [SSDT] - 378 bytes written to ssdt3.dat

Acpi table [SSDT] - 351 bytes written to ssdt4.dat

Acpi table [SSDT] - 1088 bytes written to ssdt5.dat

Acpi table [SSDT] - 141 bytes written to ssdt6.dat

Acpi table [SSDT] - 1075 bytes written to ssdt7.dat

8 binary ACPI tables extracted

nuc ~ # iasl -d *dat 2>&1 | grep Output

ASL Output: dsdt.dsl - 426096 bytes

ASL Output: ssdt1.dsl - 9929 bytes

ASL Output: ssdt2.dsl - 7673 bytes

ASL Output: ssdt3.dsl - 4371 bytes

ASL Output: ssdt4.dsl - 2919 bytes

ASL Output: ssdt5.dsl - 9649 bytes

ASL Output: ssdt6.dsl - 1323 bytes

ASL Output: ssdt7.dsl - 16934 bytes

nuc ~ # grep _BCL *dsl

nuc ~ # grep -i -e linux -e windows *dsl

dsdt.dsl: If (_OSI ("Windows 2001"))

dsdt.dsl: If (_OSI ("Windows 2001 SP1"))

dsdt.dsl: If (_OSI ("Windows 2001 SP2"))

dsdt.dsl: If (_OSI ("Windows 2006"))

dsdt.dsl: If (_OSI ("Windows 2009"))

dsdt.dsl: If (_OSI ("Windows 2012"))

dsdt.dsl: If (_OSI ("Windows 2013"))

dsdt.dsl: Name (_CID, EisaId ("PNP0D80") /* Windows-compatible System Power Management Controller */) // _CID: Compatible ID

nuc ~ #

there are strings for Windows but not for Linux.

any comment will be welcome, thank you.

[idata]

intel-2820: Thank you very much for joining the Intel® NUC communities. We are sorry to hear the NUC is not working properly.

Just to let you know, the tests performed by Intel on the NUC were done using Windows as operating system. However we know that a lot of NUC owners are using it successfully on many different Linux distros. We will do further research on this matter, in the mean time, please get in contact with the forums support for Linux, in there you will receive peer to peer assistance and the might have additional suggestions to fix this problem, please let us know the results:http://www.linuxforums.org/forum/ http://www.linuxforums.org/forum/ Any further questions, please let me know. Regards,Alberto R