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Message-ID: <a23c8b0b-ec62-437b-b876-3143f132a901@manjaro.org>
Date: Tue, 26 Aug 2025 14:28:10 +0200
From: Philip Müller <philm@...jaro.org>
To: Antheas Kapenekakis <lkml@...heas.dev>, amd-gfx@...ts.freedesktop.org
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
Alex Deucher <alexander.deucher@....com>,
Christian König <christian.koenig@....com>,
Mario Limonciello <mario.limonciello@....com>
Subject: Re: [PATCH v1 4/5] drm: panel-backlight-quirks: Add brightness mask
quirk
On 8/24/25 22:02, Antheas Kapenekakis wrote:
> 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. Summary examples are found below.
>
> 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
> Signed-off-by: Antheas Kapenekakis <lkml@...heas.dev>
> ---
> .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 7 +++++
> .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h | 6 ++++
> drivers/gpu/drm/drm_panel_backlight_quirks.c | 29 +++++++++++++++++++
> include/drm/drm_utils.h | 1 +
> 4 files changed, 43 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index 4ad80ae615a2..156f2aae6828 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -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) {
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> index b937da0a4e4a..340f9b5f68eb 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> @@ -200,6 +200,12 @@ struct amdgpu_dm_backlight_caps {
> * @aux_support: Describes if the display supports AUX backlight.
> */
> bool aux_support;
> + /**
> + * @brightness_mask: After deriving brightness, or it with this mask.
> + * This is used to workaround panels that have issues with certain
> + * brightness values.
> + */
> + u32 brightness_mask;
> /**
> * @ac_level: the default brightness if booted on AC
> */
> diff --git a/drivers/gpu/drm/drm_panel_backlight_quirks.c b/drivers/gpu/drm/drm_panel_backlight_quirks.c
> index 3d386a96e50e..78c430b07d6a 100644
> --- a/drivers/gpu/drm/drm_panel_backlight_quirks.c
> +++ b/drivers/gpu/drm/drm_panel_backlight_quirks.c
> @@ -45,6 +45,35 @@ static const struct drm_get_panel_backlight_quirk drm_panel_min_backlight_quirks
> .ident.name = "NE135A1M-NY1",
> .quirk = { .min_brightness = 1, },
> },
> + /* Have OLED Panels with brightness issue when last byte is 0/1 */
> + {
> + .dmi_match.field = DMI_SYS_VENDOR,
> + .dmi_match.value = "AYANEO",
> + .dmi_match_other.field = DMI_PRODUCT_NAME,
> + .dmi_match_other.value = "AYANEO 3",
> + .quirk = { .brightness_mask = 3, },
> + },
> + {
> + .dmi_match.field = DMI_SYS_VENDOR,
> + .dmi_match.value = "ZOTAC",
> + .dmi_match_other.field = DMI_BOARD_NAME,
> + .dmi_match_other.value = "G0A1W",
> + .quirk = { .brightness_mask = 3, },
> + },
> + {
> + .dmi_match.field = DMI_SYS_VENDOR,
> + .dmi_match.value = "ONE-NETBOOK",
> + .dmi_match_other.field = DMI_PRODUCT_NAME,
> + .dmi_match_other.value = "ONEXPLAYER F1Pro",
> + .quirk = { .brightness_mask = 3, },
> + },
> + {
> + .dmi_match.field = DMI_SYS_VENDOR,
> + .dmi_match.value = "ONE-NETBOOK",
> + .dmi_match_other.field = DMI_PRODUCT_NAME,
> + .dmi_match_other.value = "ONEXPLAYER F1 EVA-02",
> + .quirk = { .brightness_mask = 3, },
> + }
> };
>
> static bool drm_panel_min_backlight_quirk_matches(
> diff --git a/include/drm/drm_utils.h b/include/drm/drm_utils.h
> index 82eeee4a58ab..6a46f755daba 100644
> --- a/include/drm/drm_utils.h
> +++ b/include/drm/drm_utils.h
> @@ -18,6 +18,7 @@ int drm_get_panel_orientation_quirk(int width, int height);
>
> struct drm_panel_backlight_quirk {
> u16 min_brightness;
> + u32 brightness_mask;
> };
>
> const struct drm_panel_backlight_quirk *
Tested-by: Philip Müller <philm@...jaro.org>
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