Thank you as well for all your help debugging this problem. Your careful testing of the physical screen response made it possible to identify the working brightness-control method. I am also very glad that the process helped you learn something new :)
Yes, you can make the workaround persistent through GRUB. The order of lines in /etc/default/grub is not important here. What matters is adding the parameter inside the existing GRUB_CMDLINE_LINUX_DEFAULT value. Do not add it as a separate line. Open the configuration: sudo nano /etc/default/grub Find a line similar to: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" Add the parameter at the end, inside the quotation marks: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash xe.enable_dpcd_backlight=2" If that line already contains other parameters, please keep them and only append xe.enable_dpcd_backlight=2. Save the file (CTRL+O), update GRUB, and restart: sudo update-grub sudo reboot After restarting, verify the setting: cat /proc/cmdline cat /sys/module/xe/parameters/enable_dpcd_backlight The first command should include xe.enable_dpcd_backlight=2 and the second should return 2. This applies the workaround to future kernel boots as well. To remove it later, delete only xe.enable_dpcd_backlight=2 from the same line, run sudo update-grub again, and restart. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2163244 Title: Ubuntu 26.04 LTS -- Lenovo Yoga 7 Pro 15IPH11 Screen Brightness not Working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2163244/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
