Bruno Beaufils, thank you for performing the requested test. As a potential WORKAROUND, could you please add each of the following kernel boot parameters individually and advise if you may adjust the backlight:
acpi_backlight=vendor
video.use_bios_initial_backlight=0
As well, if you remove the nomodeset kernel parameter, does it change anything?
Bruno Beaufils, thank you for performing the requested test. As a potential WORKAROUND, could you please add each of the following kernel boot parameters individually and advise if you may adjust the backlight: vendor bios_initial_ backlight= 0
acpi_backlight=
video.use_
As well, if you remove the nomodeset kernel parameter, does it change anything?