Thank you. Your results are already very useful. GNOME is changing the correct intel_backlight device, but the physical panel does not react. No messages appearing in dmesg during slider movement is normal and does not mean that you did anything incorrectly :)
Let's do one more diagnostic step, please execute following commands on RC5 (I think we can skip testing RC4 for now, as you've been hitting the same issue there): uname -r cat /sys/module/xe/parameters/enable_dpcd_backlight readlink -f /sys/bus/wmi/devices/603E9613-EF25-4338-A3D0-C46177516DB7/driver || echo "WMI device is not bound to a driver" sudo cat /sys/kernel/debug/dri/*/i915_display_info And also save the kernel log with: sudo journalctl -b -k --no-pager > ~/brightness-rc5-kernel.log This creates brightness-rc5-kernel.log in your home directory. Please attach that file to the bug report. -- 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
