The brightness of the screen cannot be adjusted with either the buttons or the slider.

[albertoiNET]

Brightness is always at 100% and cannot be adjusted with either the FN brightness buttons or the Unity top bar slider.

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: linux-image-4.13.0-36-generic 4.13.0-36.40
ProcVersionSignature: Ubuntu 4.13.0-36.40-generic 4.13.13
Uname: Linux 4.13.0-36-generic x86_64
ApportVersion: 2.20.7-0ubuntu3.7
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: albertoinet 1199 F.... pulseaudio
 /dev/snd/controlC0: albertoinet 1199 F.... pulseaudio
CurrentDesktop: ubuntu:GNOME
Date: Mon Feb 26 20:49:16 2018
HibernationDevice: RESUME=UUID=56535002-bba2-4658-b57f-75ba5bb87d4f
InstallationDate: Installed on 2018-02-25 (1 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Release amd64 (20180105.1)
MachineType: Micro-Star International Co., Ltd. GT72VR 7RD
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=es_ES.UTF-8
 SHELL=/bin/bash
ProcFB: 0 nouveaufb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.13.0-36-generic.efi.signed root=/dev/mapper/ubuntu--vg-root ro quiet splash acpi_osi=Linux vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.13.0-36-generic N/A
 linux-backports-modules-4.13.0-36-generic N/A
 linux-firmware 1.169.3
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/27/2017
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: E1785IMS.30E
dmi.board.asset.tag: Default string
dmi.board.name: MS-1785
dmi.board.vendor: Micro-Star International Co., Ltd.
dmi.board.version: REV:1.0
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 10
dmi.chassis.vendor: Micro-Star International Co., Ltd.
dmi.chassis.version: Default string
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrE1785IMS.30E:bd10/27/2017:svnMicro-StarInternationalCo.,Ltd.:pnGT72VR7RD:pvrREV1.0:rvnMicro-StarInternationalCo.,Ltd.:rnMS-1785:rvrREV1.0:cvnMicro-StarInternationalCo.,Ltd.:ct10:cvrDefaultstring:
dmi.product.family: GT
dmi.product.name: GT72VR 7RD
dmi.product.version: REV:1.0
dmi.sys.vendor: Micro-Star International Co., Ltd.

[albertoiNET (albertoinet)]

sudo lspci -vnvn > lspci-vnvn.log

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[Joseph Salisbury (jsalisbury)]

Did this issue start happening after an update/upgrade? Was there a prior kernel version where you were not having this particular problem?

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.16 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.16-rc3

[albertoiNET (albertoinet)]

Bug exist on Kernel Upstream mainline

[Kai-Heng Feng (kaihengfeng)]

The graphic card is "GeForce GTX 1060 Mobile", which I don't think nouveau has good support (yet).

Try to use proprietary Nvidia driver.

[albertoiNET (albertoinet)]

I used a nvidia propietary driver, but also doesn't work. In this askubuntu I'm tested multiples things, without success

https://askubuntu.com/questions/1010405/the-brightness-of-laptop-screen-cannot-be-adjusted-with-either-the-buttons-or-th/1010420#1010420

[Kai-Heng Feng (kaihengfeng)]

What's the output of `find /sys/class/backlight`?

[albertoiNET (albertoinet)]

This is the ouput @kaihengfeng

$ find /sys/class/backlight
/sys/class/backlight
/sys/class/backlight/acpi_video0

[albertoiNET (albertoinet)]

More info on Askubuntu

https://askubuntu.com/questions/1010405/the-brightness-of-laptop-screen-cannot-be-adjusted-with-either-the-buttons-or-th/1011557

[Kai-Heng Feng (kaihengfeng)]

I think you need to install nvidia driver:

$ sudo ubuntu-drivers auto install

[albertoiNET (albertoinet)]

I've got installed nvidia drivers

[Kai-Heng Feng (kaihengfeng)]

So does the issue get solved?

[albertoiNET (albertoinet)]

No

[Kai-Heng Feng (kaihengfeng)]

Try kernel parameter "acpi_backlight=video" and "acpi_backlight=vendor"

[albertoiNET (albertoinet)]

I tried a lot of thing. Please see this topic for see the list that things than doesn't work

https://askubuntu.com/questions/1010405/the-brightness-of-laptop-screen-cannot-be-adjusted-with-either-the-buttons-or-th/1011557

[Kai-Heng Feng (kaihengfeng)]

Does /sys/class/backlight/acpi_video0/brightness change after you use xrandr to change the brightness?

[albertoiNET (albertoinet)]

No, /sys/class/backlight/acpi_video0/brightness doesn't change after user xrandr. This value only change when with I move the brightness slider at the right top of screen.

[Kai-Heng Feng (kaihengfeng)]

Can you attach acpidump? Thanks!

[Kai-Heng Feng (kaihengfeng)]

Also, do you add "acpi_osi=Linux" for any reason?

[albertoiNET (albertoinet)]

This is the acpidump. I added "acpi_osi=Linux" for recomendations. But now it not set.

Thanks

[Kai-Heng Feng (kaihengfeng)]

Sorry for the late reply.

Can you try 18.04? Without any "acpi_osi=" parameter of course...

Also, please ask the vendor which device should control the brightness? I can see the PEGP's _BCM method reference to GFX0's _BCM, maybe it can only be called on GFX0 directly?

[Launchpad Janitor (janitor)]

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