Since I upgraded from Ubuntu 19.10 to 20.04 (Gnome 3.36.1) I have some problems with the screen of my laptop (Clevo N151ZU, i7 8565U):
- I can't change the screen brigthness with my keyboard (Fn + F8/9)
- I can't change the screen brightness with the menu in the right top corner (where you can change the volume, shutdown the pc, etc.)
- I can't change the screen brightness in the Gnome settings
-My laptop display is shown as "Unknown Display" in the Gnome display settings
- I can't change the Hz and the resolution (only avaiable option is 1920×1080) in the Gnome display settings
-xbacklight is installed, the commands xbacklight -set 0, xbacklight -set 100 do nothing
- When I close the lid of my laptop, it doesn't go to standby (I set the option "go to standby, when lid is closed" in the Gnome tweak tool)
- The screen stays black, when I wake the laptop up from the standby (keyboard lights turn on, etc.)
On boot I get the error message:
i915: `' invalid for parameter `enable_dpcd_backlight
I tried it with these options in the
GRUB_CMDLINE_LINUX_DEFAULT line in
acpi_backlight=vendor, acpi_backlight=video, acpi_backlight=native
sudo update-grub and a reboot after it, of course), didn't change anything.
I installed the
xserver-xorg-video-intel, no differences.
Some system information:
$ glxinfo | grep "OpenGL core profile version string" OpenGL core profile version string: 3.3 (Core Profile) Mesa 20.0.4
ls /sys/class/backlight/ returns nothing.
$ sudo find /sys/ -type f -iname '*brightness*' /sys/devices/platform/i8042/serio0/input/input4/input4::capslock/brightness /sys/devices/platform/i8042/serio0/input/input4/input4::capslock/max_brightness /sys/devices/platform/i8042/serio0/input/input4/input4::scrolllock/brightness /sys/devices/platform/i8042/serio0/input/input4/input4::scrolllock/max_brightness /sys/devices/platform/i8042/serio0/input/input4/input4::numlock/brightness /sys/devices/platform/i8042/serio0/input/input4/input4::numlock/max_brightness /sys/devices/platform/tuxedo_keyboard/brightness /sys/devices/pci0000:00/0000:00:1d.1/0000:3a:00.0/leds/phy0-led/brightness /sys/devices/pci0000:00/0000:00:1d.1/0000:3a:00.0/leds/phy0-led/max_brightness /sys/module/video/parameters/hw_changes_brightness /sys/module/video/parameters/brightness_switch_enabled /sys/module/tuxedo_keyboard/parameters/brightness