I can confirm the same issue on a Lenovo E31 with Intel HD Graphics 5500 (Broadwell), running elementary OS 8.1 / Ubuntu 24.04.3 with kernel 7.0.0-28-generic. Before the workaround, suspend resumed with a black display, and brightness hotkeys changed the on-screen indicator and /sys/class/backlight/intel_backlight values but did not visibly change panel brightness. My suspend log also contained the assert_can_disable_lcpll i915 warning. Adding i915.enable_dpcd_backlight=0 to GRUB_CMDLINE_LINUX_DEFAULT, running sudo update-grub, and rebooting fixed both the suspend/resume display problem and physical brightness control.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2161826 Title: i915 DPCD backlight bug on Broadwell (ThinkPad T450s): black screen after suspend + broken brightness, fixed by i915.enable_dpcd_backlight=0 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2161826/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
