Mario, how about trying with "acpi_backlight=vendor" and also "dell_laptop.backlight=0" (goal still being to leave only intel_backlight).
Please report what you end up with in /sys/class/backlight in that case, and then whether you still see the flicker when you adjust the intel_backlight/brightness value.
Mario, how about trying with "acpi_backlight =vendor" and also "dell_laptop. backlight= 0" (goal still being to leave only intel_backlight).
Please report what you end up with in /sys/class/ backlight in that case, and then whether you still see the flicker when you adjust the intel_backlight /brightness value.