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silverhikari

Member

Registered: 2018-09-09

Posts: 19

display on thinkpad s230u randomly dimming and brightening. Plasma

kernel: 6.2
DE: Plasma
backlight-driver/device: intel-backlight
driver: i915
inxi log: https://paste.ee/p/OupEI

journalctl -k log:  https://paste.ee/p/bSq98

laptop screen seems to randomly change brightness with behavior changing when ever it happens as sometimes it will dim and brighten with it never going below 30 and if set higher such as 85 will reset to 30. other times it will continue to gradually over use dim in stages with me manually increasing the brightness to reset it but will continue to dim until the screen shutsoff. the laptop has a bad battery(not lasting long after being removed from charger) so i keep it plugged in the wall for all of it use so i don't think that could be a problem. i have also disabled all setting in the KDE power settings menu.

i have also updated and install the intel-microcode and added it to grub but that has not seem to do anything and i have also updated the bios to the latest version available for the model from Lenovo.

i have also tested this laptop on windows 10 and the problem did not happen, so it seems to be dealing with software more then something wrong with the hardware.

Strike0

Member

From: Germany

Registered: 2011-09-05

Posts: 1,489

Re: display on thinkpad s230u randomly dimming and brightening. Plasma

Mar 21 18:36:02 test-laptop-arch kernel: thinkpad_acpi: This ThinkPad has standard ACPI backlight brightness control, supported by the ACPI video driver
Mar 21 18:36:02 test-laptop-arch kernel: thinkpad_acpi: Disabling thinkpad-acpi brightness events by default...

I get the same log for a related model. Not using Plasma and here brightness always returned to 100% on its own after resume (opposite to your issue). I found brightnessctl manages to save settings and make them persistent.

silverhikari

Member

Registered: 2018-09-09

Posts: 19

Re: display on thinkpad s230u randomly dimming and brightening. Plasma

well after installing brightnessctl i can control the brightness with the commands, but it seems the system will randomly set a brightness setting and trying to dim or brighten pass that point will reset to that initial version and this minimum brightness will change after sometime either after dimming for not being used(even though that was disabled) or after some random amount of time. tried changing the minimum brightness value using brightnessctl by that seems to have no effect

EDIT: also noticed that at the session manager sddm that the brightness is unaffected and cannot be controlled by the keys on the keyboard.

EDIT 2: noticed something else strange the screen still dims after a few seconds even though that was disabled in plasma energy setting

Last edited by silverhikari (2023-03-26 03:05:37)

silverhikari

Member

Registered: 2018-09-09

Posts: 19

Re: display on thinkpad s230u randomly dimming and brightening. Plasma

Found out what was the problem. this drive was originally on a different laptop that broke but what the problem was on that laptop a long time ago i install clight and clightd(which use the webcam as a ambient light sensor) but it seems clight can not detect the webcam correctly cause it to glitch out on turning on the system, and one of settings that is enabled by default is autocalibrate which will change the brightness automatically which caused the random brightness and resetting brightness problems that i have found and removing this seems to have fixed the brightness problems. i forgot that was enabled as this drive has not been used for a few months and only recently placed it in to a working laptop.

Last edited by silverhikari (2023-03-26 03:33:57)

Strike0

Member

From: Germany

Registered: 2011-09-05

Posts: 1,489

Re: display on thinkpad s230u randomly dimming and brightening. Plasma

Good find with clight.
FWIW I'm not using Plasma, but I still have the random brightness reset issue you mention on gnome after a resume-from-ram. Yet, it only needs a click on the settings-brightness slider to pick up the default saved with brightnessctl here. Not using gnome that much, which is why I stopped investigating it further. After a fresh boot, saved brightness stays set.