Hi All, really appreciated any help in advance.
I have same issue on every wakeup from sleep. laptop is being started correctly, I can see screen from some angles, but lcd backlight is switched off. I did some tests, like switching terminals, etc, but light is always switched off until next reboot.
I have appended acpi_backlight=vendor to the Grub booting line, which solved my problem with HW brightness controll, but suspend / wakeup is still not working as expected.