[OEM-5.17/J][PATCH 0/3] Fix oled brightness set above frame-average luminance

Aaron Ma aaron.ma at canonical.com
Tue Aug 23 14:50:18 UTC 2022

BugLink: https://bugs.launchpad.net/bugs/1978986

The brightness is not changed obviously during 200 to 255 on AMD
or 400 to 512 on Intel.

Read HDR meta to detect the max and min luminance.
max_cll defines the content light luminance for individual pixel.
max_fall defines frame-average level luminance.
Use max_fall value instead of max_cll as a limit for brightness control.

Verified on AMD Cezanne, Barcelo, Rembrandt and Intel ADL, also on LCD panel and
OLED panel. The brightness is changed more obivously on OLED panel, and
no affect on LCD panel.

[Where problems could occur]
Low risk, It may cause the max brightness can't be set.

All 3 patches are in drm-misc tree.

Jouni Högander (3):
  UBUNTU: SAUCE: drm: New function to get luminance range based on
    static hdr metadata
  UBUNTU: SAUCE: drm/amdgpu_dm: Rely on split out luminance calculation function
  UBUNTU: SAUCE: drm/i915: Use luminance range calculated during edid parsing

 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 35 ++-----------
 drivers/gpu/drm/drm_edid.c                    | 52 ++++++++++++++++++-
 .../drm/i915/display/intel_dp_aux_backlight.c | 15 +++++-
 include/drm/drm_connector.h                   | 21 ++++++++
 4 files changed, 89 insertions(+), 34 deletions(-)


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