This is not a bug in the kernel/config. The reason is in the xrandr.
Adding --brightness=1.0 to xrandr arguments solves the problem.
This reverts commit 94ac5e3703.
CONFIG_PCIEASPM_POWERSAVE=y
|
V
CONFIG_PCIEASPM_DEFAULT=y
CONFIG_INTEL_MENLOW=m
CONFIG_ACPI_WMI=m
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V
CONFIG_INTEL_RST=m
CONFIG_INTEL_SMARTCONNECT=m
|
V
CONFIG_SAMSUNG_LAPTOP=m -> ?