linux-kernel - [PATCH v1 4/5] drm: panel-backlight-quirks: Add brightness mask quirk

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20250824200202.1744335-5-lkml@antheas.dev>
Date: Sun, 24 Aug 2025 22:02:01 +0200
From: Antheas Kapenekakis <lkml@...heas.dev>
To: amd-gfx@...ts.freedesktop.org
Cc: dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org,
	philm@...jaro.org,
	Alex Deucher <alexander.deucher@....com>,
	Christian König <christian.koenig@....com>,
	Mario Limonciello <mario.limonciello@....com>,
	Antheas Kapenekakis <lkml@...heas.dev>
Subject: [PATCH v1 4/5] drm: panel-backlight-quirks: Add brightness mask quirk

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 *
-- 
2.50.1