[PATCH v3 0/2] drm: minimum backlight overrides and implementation for amdgpu

[Thomas Weißschuh]

The value of "min_input_signal" returned from ATIF on a Framework AMD 13
is "12". This leads to a fairly bright minimum display backlight.

Add a generic override helper for the user to override the settings
provided by the firmware through the kernel cmdline.
Also add amdgpu as a user of that helper.

One solution would be a fixed firmware version, which was announced but
has no timeline.

This helper does conflict with the mode override via the cmdline.
Only one can be specified.
IMO the mode override can be extended to also handle "min-brightness"
when that becomes necessary.

---
Changes in v3:
- Switch to cmdline override parameter
- Link to v2: https://lore.kernel.org/r/20240623-amdgpu-min-backlight-quirk-v2-0-cecf7f49da9b@weissschuh.net

Changes in v2:
- Introduce proper drm backlight quirk infrastructure
- Quirk by EDID and DMI instead of only DMI
- Limit quirk to only single Framework 13 matte panel
- Link to v1: https://lore.kernel.org/r/20240610-amdgpu-min-backlight-quirk-v1-1-8459895a5b2a@weissschuh.net

---
Thomas Weißschuh (2):
      drm/connector: add drm_connector_get_cmdline_min_brightness_override()
      drm/amd/display: implement minimum brightness override

 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c |  6 ++++
 drivers/gpu/drm/drm_connector.c                   | 34 +++++++++++++++++++++++
 include/drm/drm_connector.h                       |  2 ++
 3 files changed, 42 insertions(+)
---
base-commit: 36821612eb3091a21f7f4a907b497064725080c3
change-id: 20240610-amdgpu-min-backlight-quirk-8402fd8e736a

Best regards,
-- 
Thomas Weißschuh <linux at weissschuh.net>