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Screen brightness control disappeared

asked 2018-04-27 13:16:57 -0500

romaf gravatar image

Hi, I've got a problem after update from kernel-4.15.16-300.fc27.x8664 to kernel-4.15.17-300.fc27.x8664 and in the newest version released by Fedora through dnf: kernel-4.16.3-200.fc27.x86_64 it happens also. If I boot to 4.15.16 again problem no exists.

It's laptop with Fedora 27, Gnome, Intel Core i7 3540M with Intel Graphics and nVidia 640M on the board.

After an update to the new kernel I cannot control brightness of the screen (keyboard shortcuts doesn't work for brightness only; I cannot see controls in gnome environment), and gnome control panel shows inaccurate settings for this screen (for example I can choose frequency of 120Hz in 60Hz laptop's screen). No other screen is connected now.

In gnome logs I can see an error with nouveau: nouveau 0000:01:00.0: devinit: 0x00006331[0]: script needs connector type kernel device: +pci:0000:01:00.0 priority: 6

Can You please tell me what's wrong? I changed nothing, only update via DNF.

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answered 2018-04-30 13:00:29 -0500

ozeszty gravatar image

updated 2018-04-30 18:11:39 -0500

Hi, it might be regression after 5928c281524fe451114e04f1dfa11246a37e859f commit. Report it in Red Hat Bugzilla with kernel as component.


It should be fixed in kernel 4.16.6 (commit 53fa1f6e8a5958da698a31edf366ffe90596b490), you can install it manually now or use below temporary fix (just remember to remove it later):

follow those steps to temporarily add video.only_lcd=0 into kernel boot parameters. If that enables backlight control, add this parameter permanently (you can use any other editor instead of nano):

nano /etc/default/grub

find rhgb quiet and change it into rhgb quiet video.only_lcd=0, save changes (Ctrl+O), exit editor (Ctrl+X) and run:

grub2-mkconfig -o /boot/grub2/grub.cfg

or for UEFI systems:

grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg
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Asked: 2018-04-27 13:16:57 -0500

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Last updated: Apr 30 '18