@Tito and other folks with /sys/class/backlight/acpi_video0:
To disable the "acpi_video0" backlight, boot with this kernel parameter[1]:
acpi_backlight=vendor
However note that when I do so on my Lenovo Thinkpad, acpi_video0 disappears but then /sys/class/backlight/thinkpad_backlight appears in its place, so...
To disable "thinkpad_backlight", boot with this kernel parameter also:
thinkpad_acpi.brightness_enable=0
Tito, please try booting with both of those parameters (together) and report your results.
@Tito and other folks with /sys/class/ backlight/ acpi_video0:
To disable the "acpi_video0" backlight, boot with this kernel parameter[1]:
acpi_ backlight= vendor
However note that when I do so on my Lenovo Thinkpad, acpi_video0 disappears but then /sys/class/ backlight/ thinkpad_ backlight appears in its place, so...
To disable "thinkpad_ backlight" , boot with this kernel parameter also:
thinkpad_ acpi.brightness _enable= 0
Tito, please try booting with both of those parameters (together) and report your results.
[1] To add kernel boot parameters, append them to the "linux" or "kernel" boot line as demonstrated here: /help.ubuntu. com/community/ Grub2#Editing% 20Menus% 20During% 20Boot /help.ubuntu. com/community/ BootOptions# Change% 20Boot% 20Options% 20Temporarily% 20For%20An% 20Existing% 20Installation
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