linux-kernel - Re: [PATCH v1 5/5] drm: panel-backlight-quirks: Add Steam Decks

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Message-ID: <f1ba9808-64a5-4d64-a4ef-b2a95cebae94@amd.com>
Date: Mon, 25 Aug 2025 11:47:08 -0500
From: Mario Limonciello <mario.limonciello@....com>
To: Antheas Kapenekakis <lkml@...heas.dev>, 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>
Subject: Re: [PATCH v1 5/5] drm: panel-backlight-quirks: Add Steam Decks

On 8/24/2025 3:02 PM, Antheas Kapenekakis wrote:
> On the SteamOS kernel, Valve universally makes minimum brightness 0
> for all devices. SteamOS is (was?) meant for the Steam Deck, so
> enabling it universally is reasonable. However, it causes issues in
> certain devices. Therefore, introduce it just for the Steam Deck here.
> 
> SteamOS kernel does not have a public mirror, but this replaces commit
> 806dd74bb225 ("amd/drm: override backlight min value from 12 -> 0")
> in the latest, as of this writing, SteamOS kernel (6.11.11-valve24).
> See unofficial mirror reconstructed from sources below.
> 
> Link: https://gitlab.com/evlaV/linux-integration/-/commit/806dd74bb225
> Signed-off-by: Antheas Kapenekakis <lkml@...heas.dev>
> ---

Directionally I agree with this commit in favor of what the downstream 
kernel tree has that you linked above.

But I would rather see it sent alone and not tied to a series to 
overhaul how quirks work.  If it's sent alone we should be able to get 
it reviewed pretty easily and in drm-misc-fixes.

>   drivers/gpu/drm/drm_panel_backlight_quirks.c | 17 ++++++++++++++++-
>   1 file changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_panel_backlight_quirks.c b/drivers/gpu/drm/drm_panel_backlight_quirks.c
> index 78c430b07d6a..5c24f4a86519 100644
> --- a/drivers/gpu/drm/drm_panel_backlight_quirks.c
> +++ b/drivers/gpu/drm/drm_panel_backlight_quirks.c
> @@ -73,7 +73,22 @@ static const struct drm_get_panel_backlight_quirk drm_panel_min_backlight_quirks
>   		.dmi_match_other.field = DMI_PRODUCT_NAME,
>   		.dmi_match_other.value = "ONEXPLAYER F1 EVA-02",
>   		.quirk = { .brightness_mask = 3, },
> -	}
> +	},
> +	/* Steam Deck models */
> +	{
> +		.dmi_match.field = DMI_SYS_VENDOR,
> +		.dmi_match.value = "Valve",
> +		.dmi_match_other.field = DMI_PRODUCT_NAME,
> +		.dmi_match_other.value = "Jupiter",
> +		.quirk = { .min_brightness = 1, },
> +	},
> +	{
> +		.dmi_match.field = DMI_SYS_VENDOR,
> +		.dmi_match.value = "Valve",
> +		.dmi_match_other.field = DMI_PRODUCT_NAME,
> +		.dmi_match_other.value = "Galileo",
> +		.quirk = { .min_brightness = 1, },
> +	},
>   };
>   
>   static bool drm_panel_min_backlight_quirk_matches(