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

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Message-ID: 
 <CAGwozwHuHnwq+OyFLVfMu15LPUKeX3Nz=_uPC50FS2ZFEhWhOg@mail.gmail.com>
Date: Mon, 25 Aug 2025 23:20:00 +0200
From: Antheas Kapenekakis <lkml@...heas.dev>
To: Mario Limonciello <mario.limonciello@....com>
Cc: amd-gfx@...ts.freedesktop.org, 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 Mon, 25 Aug 2025 at 23:05, Mario Limonciello
<mario.limonciello@....com> wrote:
>
> On 8/25/2025 4:02 PM, Antheas Kapenekakis wrote:
> > On Mon, 25 Aug 2025 at 18:47, Mario Limonciello
> > <mario.limonciello@....com> wrote:
> >>
> >> 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.
> >
> > That's a good idea. However, this commit relies on patch 1 and 3, as
> > it has no edid information and uses a second match.
>
> The EDID half should be a solvable problem.  IE the EDIDs for Steam Deck
> and Steam Deck OLED are known quantities, or a least trivial to dump.
>
> And once you have the EDID in place I'm not sure if you need a second
> match anymore or not really (at least for SD/SD OLED).

Yeah. Perhaps for those you are right. The information should be in
gamescope in github. I think there are four panels.

I need to start logging edid information on bug reports though,
otherwise I would not say it is trivial, esp. for the four devices
that need the luminance quirk.

> >
> > Antheas
> >
> >>>    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(
> >>
> >>
> >
>
>