cant adjust brightness and no file under sys/class/backlight

[paddy-rice]

I can't change the brightness of my display (the keyboard shortcut nor the setting helps), and there is no file under sys/class/backlight.

$ sudo find /sys/ -type f -iname '*brightness*' gives me following results:

/sys/devices/platform/thinkpad_acpi/leds/platform::mute/brightness
/sys/devices/platform/thinkpad_acpi/leds/platform::mute/max_brightness
/sys/devices/platform/thinkpad_acpi/leds/tpacpi::power/brightness
/sys/devices/platform/thinkpad_acpi/leds/tpacpi::power/max_brightness
/sys/devices/platform/thinkpad_acpi/leds/tpacpi::lid_logo_dot/brightness
/sys/devices/platform/thinkpad_acpi/leds/tpacpi::lid_logo_dot/max_brightness
/sys/devices/platform/thinkpad_acpi/leds/tpacpi::standby/brightness
/sys/devices/platform/thinkpad_acpi/leds/tpacpi::standby/max_brightness
/sys/devices/platform/thinkpad_acpi/leds/tpacpi::thinkvantage/brightness
/sys/devices/platform/thinkpad_acpi/leds/tpacpi::thinkvantage/max_brightness
/sys/devices/platform/thinkpad_acpi/leds/tpacpi::kbd_backlight/brightness
/sys/devices/platform/thinkpad_acpi/leds/tpacpi::kbd_backlight/brightness_hw_changed
/sys/devices/platform/thinkpad_acpi/leds/tpacpi::kbd_backlight/max_brightness
/sys/devices/platform/thinkpad_acpi/leds/platform::micmute/brightness
/sys/devices/platform/thinkpad_acpi/leds/platform::micmute/max_brightness
/sys/devices/platform/i8042/serio0/input/input3/input3::numlock/brightness
/sys/devices/platform/i8042/serio0/input/input3/input3::numlock/max_brightness
/sys/devices/platform/i8042/serio0/input/input3/input3::capslock/brightness
/sys/devices/platform/i8042/serio0/input/input3/input3::capslock/max_brightness
/sys/devices/platform/i8042/serio0/input/input3/input3::scrolllock/brightness
/sys/devices/platform/i8042/serio0/input/input3/input3::scrolllock/max_brightness
/sys/devices/pci0000:00/0000:00:02.1/0000:01:00.0/net/enp1s0f0/enp1s0f0-2::lan/brightness
/sys/devices/pci0000:00/0000:00:02.1/0000:01:00.0/net/enp1s0f0/enp1s0f0-2::lan/max_brightness
/sys/devices/pci0000:00/0000:00:02.1/0000:01:00.0/net/enp1s0f0/enp1s0f0-1::lan/brightness
/sys/devices/pci0000:00/0000:00:02.1/0000:01:00.0/net/enp1s0f0/enp1s0f0-1::lan/max_brightness
/sys/devices/pci0000:00/0000:00:02.1/0000:01:00.0/net/enp1s0f0/enp1s0f0-0::lan/brightness
/sys/devices/pci0000:00/0000:00:02.1/0000:01:00.0/net/enp1s0f0/enp1s0f0-0::lan/max_brightness
/sys/devices/virtual/sound/ctl-led/speaker/brightness
/sys/devices/virtual/sound/ctl-led/mic/brightness
/sys/module/video/parameters/hw_changes_brightness
/sys/module/video/parameters/brightness_switch_enabled
/sys/module/thinkpad_acpi/parameters/brightness_enable
/sys/module/thinkpad_acpi/parameters/brightness_mode

[paddy-rice]

[Solved]

Change grub by "sudo gedit /etc/default/grub"

GRUB_TIMEOUT=-1 #10 to -1
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux" # quiet splash nomodest to quiet splash acpi_osi=Linux
GRUB_CMDLINE_LINUX="acpi_backlight=native" # vendor to native

save, update then restart:
sudo update-grub


After restart, the folder is back, and keyboard shortcut is working too.



Ref: https://askubuntu.com/questions/8214...kernel-version

[paddy-rice]

The filesystem shows like this:

/sys/class/backlight/amdgpu_bl1$ ls
actual_brightness brightness max_brightness scale type
bl_power device power subsystem uevent