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drm: panel-backlight-quirks: Add brightness mask quirk

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Certain OLED devices malfunction on specific brightness levels.
Specifically, when DP_SOURCE_BACKLIGHT_LEVEL is written to with
the first byte being 0x00 and sometimes 0x01, the panel forcibly
turns off until the device sleeps again.

Below are some examples. This was found by iterating over brighness
ranges while printing DP_SOURCE_BACKLIGHT_LEVEL. It was found that
the screen would malfunction on specific values, and some of them
were collected.

Therefore, introduce a quirk where the minor byte of brightness is
OR'd with 0x03 to avoid the range of invalid values.

This quirk was tested by removing the workarounds and iterating
from 0 to 50_000 value ranges with a cadence of 0.2s/it. The
range of the panel is 1000...400_000, so the values were slightly
interpolated during testing. The custom brightness curve added on
6.15 was disabled.

 86016:  10101000000000000
 86272:  10101000100000000
 87808:  10101011100000000
251648: 111101011100000000
251649: 111101011100000001

 86144:  10101000010000000
 87809:  10101011100000001
251650: 111101011100000010

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3803
Tested-by: Philip Müller <philm@manjaro.org>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Antheas Kapenekakis <lkml@antheas.dev>
Link: https://lore.kernel.org/r/20250829145541.512671-5-lkml@antheas.dev
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
This commit is contained in:
Antheas Kapenekakis
2025-08-29 16:55:39 +02:00
committed by Mario Limonciello (AMD)
parent f7033fab81
commit aef10b1138
4 changed files with 49 additions and 0 deletions
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7
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
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@@ -3662,6 +3662,9 @@ static void update_connector_ext_caps(struct amdgpu_dm_connector *aconnector)
if (panel_backlight_quirk->min_brightness)
caps->min_input_signal =
panel_backlight_quirk->min_brightness - 1;
if (panel_backlight_quirk->brightness_mask)
caps->brightness_mask =
panel_backlight_quirk->brightness_mask;
}
}
@@ -4862,6 +4865,10 @@ static void amdgpu_dm_backlight_set_level(struct amdgpu_display_manager *dm,
brightness = convert_brightness_from_user(caps, dm->brightness[bl_idx]);
link = (struct dc_link *)dm->backlight_link[bl_idx];
/* Apply brightness quirk */
if (caps->brightness_mask)
brightness |= caps->brightness_mask;
/* Change brightness based on AUX property */
mutex_lock(&dm->dc_lock);
if (dm->dc->caps.ips_support && dm->dc->ctx->dmub_srv->idle_allowed) {