[Bug 2156312] Re: Internal display black screen on Intel Lunar Lake with eDP panel

This bug is awaiting verification that the linux-nvidia/7.0.0-1016.16 kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-resolute-linux-nvidia' to 'verification-done- resolute-linux-nvidia'. If the problem still exists, change the tag 'verification-needed-resolute-linux-nvidia' to 'verification-failed- resolute-linux-nvidia'. If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you! ** Tags added: kernel-spammed-resolute-linux-nvidia-v2 verification-needed-resolute-linux-nvidia -- You received this bug notification because you are subscribed to linux in Ubuntu. Matching subscriptions: Bgg, Bmail, Nb https://bugs.launchpad.net/bugs/2156312 Title: Internal display black screen on Intel Lunar Lake with eDP panel Status in HWE Next: New Status in linux package in Ubuntu: Invalid Status in linux-oem-6.17 package in Ubuntu: Invalid Status in linux source package in Noble: Invalid Status in linux-oem-6.17 source package in Noble: Fix Released Status in linux source package in Questing: Fix Released Status in linux-oem-6.17 source package in Questing: Invalid Status in linux source package in Resolute: Fix Released Status in linux-oem-6.17 source package in Resolute: Invalid Bug description: [Impact] Internal display goes black after login on Intel Lunar Lake systems with an eDP panel. The external monitor works. The internal display shows as disabled in display settings and cannot be enabled. Hits 100% on affected hardware (3 units, 15/15 attempts). The bug is caused by LOBF (Link Off Between Frames) being enabled on platforms that use the legacy VRR timing generator. Those platforms do not meet the bspec requirement for LOBF (Always-on VRR TG with fixed refresh rate mode). Enabling LOBF incorrectly causes the display to go dark. [Fix] Replace the raw vmin/vmax/flipline comparison with the proper bspec checks: - intel_vrr_always_use_vrr_tg() to gate LOBF on platforms with Always-on VRR TG - intel_vrr_is_fixed_rr() to confirm fixed refresh rate mode Backported from upstream commit 8a517b1e6d8b, merged in v7.1-rc1. [Test Plan] Boot on affected Intel Lunar Lake hardware with an eDP panel. Without patch: internal display is black after login; shows as disabled in display settings. With patch: internal display works normally after login. [Where problems could occur] Could affect intel_alpm.c LOBF configuration logic in the i915 driver. If intel_vrr_always_use_vrr_tg() or intel_vrr_is_fixed_rr() return wrong results on a platform, LOBF would be incorrectly blocked, and Panel Replay power savings would be lost on those machines. The display would still work — it would just not enter LOBF mode. To manage notifications about this bug go to: https://bugs.launchpad.net/hwe-next/+bug/2156312/+subscriptions