[PATCH] ACPI/backlight: Force backlight native for Clevo NL5xRU and

[PATCH] ACPI/backlight: Force backlight native for Clevo NL5xRU and

[Werner Sembach]

This patch works around a bug appearing on at least two Clevo devices.
I also put some effort in finding the root cause for this bug to fix it in
general: https://bugzilla.kernel.org/show_bug.cgi?id=215683
I could pinpoint it down where it happens, but could use some ideas for
cleanly fixing it.

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

[Werner Sembach]

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@tuxedocomputers.com>
Cc: stable@vger.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

Re: [PATCH] ACPI/backlight: Force backlight native for Clevo NL5xRU and NL5xNU

[Rafael J. Wysocki]

On Tue, Mar 15, 2022 at 8:02 PM Werner Sembach <wse@tuxedocomputers.com> wrote:
>
> 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@tuxedocomputers.com>
> Cc: stable@vger.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
> --

Applied as 5.18 material, thanks!