linux-kernel - [PATCH] ACPI/backlight: Force backlight native for Clevo NL5xRU and NL5xNU

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Date:   Tue, 15 Mar 2022 20:02:28 +0100
From:   Werner Sembach <wse@...edocomputers.com>
To:     rafael@...nel.org, lenb@...nel.org, linux-acpi@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] ACPI/backlight: Force backlight native for Clevo NL5xRU and NL5xNU

Clevo NL5xRU and NL5xNU/TUXEDO Aura 15 Gen1 and Gen2 have both a working
native and video interface. However the default detection mechanism first
registers the video interface before unregistering it again and switching
to the native interface during boot. This results in a dangling SBIOS
request for backlight change for some reason, causing the backlight to
switch to ~2% once per boot on the first power cord connect or disconnect
event. Setting the native interface explicitly circumvents this buggy
behaviour by avoiding the unregistering process.

Signed-off-by: Werner Sembach <wse@...edocomputers.com>
Cc: stable@...r.kernel.org
---
 drivers/acpi/video_detect.c | 75 +++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)

diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c
index 4f64713e9917..becc198e4c22 100644
--- a/drivers/acpi/video_detect.c
+++ b/drivers/acpi/video_detect.c
@@ -415,6 +415,81 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 		DMI_MATCH(DMI_PRODUCT_NAME, "GA503"),
 		},
 	},
+	/*
+	 * Clevo NL5xRU and NL5xNU/TUXEDO Aura 15 Gen1 and Gen2 have both a
+	 * working native and video interface. However the default detection
+	 * mechanism first registers the video interface before unregistering
+	 * it again and switching to the native interface during boot. This
+	 * results in a dangling SBIOS request for backlight change for some
+	 * reason, causing the backlight to switch to ~2% once per boot on the
+	 * first power cord connect or disconnect event. Setting the native
+	 * interface explicitly circumvents this buggy behaviour, by avoiding
+	 * the unregistering process.
+	 */
+	{
+	.callback = video_detect_force_native,
+	.ident = "Clevo NL5xRU",
+	.matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
+		DMI_MATCH(DMI_BOARD_NAME, "NL5xRU"),
+		},
+	},
+	{
+	.callback = video_detect_force_native,
+	.ident = "Clevo NL5xRU",
+	.matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "SchenkerTechnologiesGmbH"),
+		DMI_MATCH(DMI_BOARD_NAME, "NL5xRU"),
+		},
+	},
+	{
+	.callback = video_detect_force_native,
+	.ident = "Clevo NL5xRU",
+	.matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "Notebook"),
+		DMI_MATCH(DMI_BOARD_NAME, "NL5xRU"),
+		},
+	},
+	{
+	.callback = video_detect_force_native,
+	.ident = "Clevo NL5xRU",
+	.matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
+		DMI_MATCH(DMI_BOARD_NAME, "AURA1501"),
+		},
+	},
+	{
+	.callback = video_detect_force_native,
+	.ident = "Clevo NL5xRU",
+	.matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
+		DMI_MATCH(DMI_BOARD_NAME, "EDUBOOK1502"),
+		},
+	},
+	{
+	.callback = video_detect_force_native,
+	.ident = "Clevo NL5xNU",
+	.matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "TUXEDO"),
+		DMI_MATCH(DMI_BOARD_NAME, "NL5xNU"),
+		},
+	},
+	{
+	.callback = video_detect_force_native,
+	.ident = "Clevo NL5xNU",
+	.matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "SchenkerTechnologiesGmbH"),
+		DMI_MATCH(DMI_BOARD_NAME, "NL5xNU"),
+		},
+	},
+	{
+	.callback = video_detect_force_native,
+	.ident = "Clevo NL5xNU",
+	.matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "Notebook"),
+		DMI_MATCH(DMI_BOARD_NAME, "NL5xNU"),
+		},
+	},
 
 	/*
 	 * Desktops which falsely report a backlight and which our heuristics
-- 
2.25.1