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Date:   Wed, 10 Mar 2021 21:04:58 +0100
From:   Pavel Machek <pavel@denx.de>
To:     gregkh@linuxfoundation.org
Cc:     linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        "Jasper St. Pierre" <jstpierre@mecheye.net>,
        Chris Chiu <chiu@endlessos.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: Re: [PATCH 5.10 23/49] ACPI: video: Add DMI quirk for GIGABYTE
 GB-BXBT-2807
Message-ID: <20210310200458.GA12122@amd>
References: <20210310132321.948258062@linuxfoundation.org>
 <20210310132322.685806668@linuxfoundation.org>
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Hi!

On Wed 2021-03-10 14:23:34, gregkh@linuxfoundation.org wrote:
> From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>=20
> From: Jasper St. Pierre <jstpierre@mecheye.net>

Something is funny with the From header here. But that's not main
thing -- this patch is evil.

>=20
> [ Upstream commit 25417185e9b5ff90746d50769d2a3fcd1629e254 ]
>=20
> The GIGABYTE GB-BXBT-2807 is a mini-PC which uses off the shelf
> components, like an Intel GPU which is meant for mobile systems.
> As such, it, by default, has a backlight controller exposed.
>=20
> Unfortunately, the backlight controller only confuses userspace, which
> sees the existence of a backlight device node and has the unrealistic
> belief that there is actually a backlight there!
>=20
> Add a DMI quirk to force the backlight off on this system.

> +++ b/drivers/acpi/video_detect.c
> @@ -140,6 +140,13 @@ static const struct dmi_system_id video_detect_dmi_t=
able[] =3D {
>  	},
>  	{
>  	.callback =3D video_detect_force_vendor,
> +	.ident =3D "GIGABYTE GB-BXBT-2807",
> +	.matches =3D {
> +		DMI_MATCH(DMI_SYS_VENDOR, "GIGABYTE"),
> +		DMI_MATCH(DMI_PRODUCT_NAME, "GB-BXBT-2807"),
> +		},
> +	},
> +	{
>  	.ident =3D "Sony VPCEH3U1E",
>  	.matches =3D {
>  		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),

Yup, and it looks like this fixes the problem for GIGABYTE
GB-BXBT-2807 but re-introduces the problem for Sony VPCEH3U1E, because
its .callback is now NULL.

Best regards,
								Pavel

IOW I'm suggesting this:

Signed-off-by: Pavel Machek (CIP) <pavel@denx.de>

diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c
index 811d298637cb..83cd4c95faf0 100644
--- a/drivers/acpi/video_detect.c
+++ b/drivers/acpi/video_detect.c
@@ -147,6 +147,7 @@ static const struct dmi_system_id video_detect_dmi_tabl=
e[] =3D {
 		},
 	},
 	{
+	.callback =3D video_detect_force_vendor,
 	.ident =3D "Sony VPCEH3U1E",
 	.matches =3D {
 		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),

--=20
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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