APPLIED: [SRU][Q][PATCH 0/1] Internal display black screen on Intel Lunar Lake with eDP panel

[Mehmet Basaran]

Applied to questing:linux master-next branch. Thanks.

-------------- next part --------------
AceLan Kao via kernel-team <kernel-team at lists.ubuntu.com> writes:

> From: "Chia-Lin Kao (AceLan)" <acelan.kao at canonical.com>
>
> BugLink: https://bugs.launchpad.net/bugs/2156312
>
> [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.
>
> Ankit Nautiyal (1):
>   drm/i915/alpm: Allow LOBF only for platform that have Always on VRR TG
>
>  drivers/gpu/drm/i915/display/intel_alpm.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> --
> 2.53.0
>
>
> --
> kernel-team mailing list
> kernel-team at lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 873 bytes
Desc: not available
URL: <https://lists.ubuntu.com/archives/kernel-team/attachments/20260619/de600b0d/attachment.sig>