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X-CSE-ConnectionGUID: rr+6QuegRUmbXfP3dIm97w== X-CSE-MsgGUID: uyrk4iu1TXCR4loK6taZ4A== X-IronPort-AV: E=McAfee;i="6700,10204,11162"; a="25546395" X-IronPort-AV: E=Sophos;i="6.09,285,1716274800"; d="scan'208";a="25546395" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Aug 2024 00:56:39 -0700 X-CSE-ConnectionGUID: lG7mVi4oRlqiqUXf6sr6fg== X-CSE-MsgGUID: kpoadPFQSNGgFJblkarbew== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.09,285,1716274800"; d="scan'208";a="63438975" Received: from fdefranc-mobl3.ger.corp.intel.com (HELO localhost) ([10.245.246.234]) by orviesa005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Aug 2024 00:56:33 -0700 From: Jani Nikula To: Thomas =?utf-8?Q?Wei=C3=9Fschuh?= , Alex Deucher , Christian =?utf-8?Q?K=C3=B6nig?= , David Airlie , Daniel Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Harry Wentland , Leo Li , Rodrigo Siqueira , Mario Limonciello , Matt Hartley , Kieran Levin , Hans de Goede , Xinhui Pan , Jonathan Corbet Cc: amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Dustin Howett , linux-doc@vger.kernel.org, Thomas =?utf-8?Q?Wei=C3=9Fschuh?= Subject: Re: [PATCH v4 1/3] drm: Add panel backlight quirks In-Reply-To: <20240812-amdgpu-min-backlight-quirk-v4-1-56a63ff897b7@weissschuh.net> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20240812-amdgpu-min-backlight-quirk-v4-0-56a63ff897b7@weissschuh.net> <20240812-amdgpu-min-backlight-quirk-v4-1-56a63ff897b7@weissschuh.net> Date: Tue, 13 Aug 2024 10:56:30 +0300 Message-ID: <878qx026vl.fsf@intel.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Mon, 12 Aug 2024, Thomas Wei=C3=9Fschuh wrote: > Panels using a PWM-controlled backlight source without an do not have a > standard way to communicate their valid PWM ranges. > On x86 the ranges are read from ACPI through driver-specific tables. > The built-in ranges are not necessarily correct, or may grow stale if an > older device can be retrofitted with newer panels. > > Add a quirk infrastructure with which the minimum valid backlight value > can be maintained as part of the kernel. > > Signed-off-by: Thomas Wei=C3=9Fschuh > --- > Documentation/gpu/drm-kms-helpers.rst | 3 ++ > drivers/gpu/drm/Kconfig | 4 ++ > drivers/gpu/drm/Makefile | 1 + > drivers/gpu/drm/drm_panel_backlight_quirks.c | 69 ++++++++++++++++++++++= ++++++ > include/drm/drm_utils.h | 3 ++ > 5 files changed, 80 insertions(+) > > diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/dr= m-kms-helpers.rst > index 8435e8621cc0..a26989500129 100644 > --- a/Documentation/gpu/drm-kms-helpers.rst > +++ b/Documentation/gpu/drm-kms-helpers.rst > @@ -230,6 +230,9 @@ Panel Helper Reference > .. kernel-doc:: drivers/gpu/drm/drm_panel_orientation_quirks.c > :export: >=20=20 > +.. kernel-doc:: drivers/gpu/drm/drm_panel_backlight_quirks.c > + :export: > + > Panel Self Refresh Helper Reference > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D >=20=20 > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig > index 6b2c6b91f962..9ebb8cdb535e 100644 > --- a/drivers/gpu/drm/Kconfig > +++ b/drivers/gpu/drm/Kconfig > @@ -454,6 +454,10 @@ config DRM_HYPERV > config DRM_EXPORT_FOR_TESTS > bool >=20=20 > +# Separate option as not all DRM drivers use it > +config DRM_PANEL_BACKLIGHT_QUIRKS > + tristate > + > config DRM_LIB_RANDOM > bool > default n > diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile > index 68cc9258ffc4..adf85999aee2 100644 > --- a/drivers/gpu/drm/Makefile > +++ b/drivers/gpu/drm/Makefile > @@ -92,6 +92,7 @@ drm-$(CONFIG_DRM_PANIC) +=3D drm_panic.o > obj-$(CONFIG_DRM) +=3D drm.o >=20=20 > obj-$(CONFIG_DRM_PANEL_ORIENTATION_QUIRKS) +=3D drm_panel_orientation_qu= irks.o > +obj-$(CONFIG_DRM_PANEL_BACKLIGHT_QUIRKS) +=3D drm_panel_backlight_quirks= .o >=20=20 > # > # Memory-management helpers > diff --git a/drivers/gpu/drm/drm_panel_backlight_quirks.c b/drivers/gpu/d= rm/drm_panel_backlight_quirks.c > new file mode 100644 > index 000000000000..a88e77db97c5 > --- /dev/null > +++ b/drivers/gpu/drm/drm_panel_backlight_quirks.c > @@ -0,0 +1,69 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +#include > +#include > +#include > +#include > +#include > + > +struct drm_panel_min_backlight_quirk { > + struct { > + enum dmi_field field; > + const char * const value; > + } dmi_match; > + struct drm_edid_ident ident; > + u8 min_brightness; > +}; > + > +static const struct drm_panel_min_backlight_quirk drm_panel_min_backligh= t_quirks[] =3D { > +}; > + > +static bool drm_panel_min_backlight_quirk_matches(const struct drm_panel= _min_backlight_quirk *quirk, > + const struct drm_edid *edid) > +{ > + if (!dmi_match(quirk->dmi_match.field, quirk->dmi_match.value)) > + return false; > + > + if (!drm_edid_match(edid, &quirk->ident)) > + return false; > + > + return true; > +} > + > +/** > + * drm_get_panel_min_brightness_quirk - Get minimum supported brightness= level for a panel. > + * @edid: EDID of the panel to check > + * > + * This function checks for platform specific (e.g. DMI based) quirks > + * providing info on the minimum backlight brightness for systems where = this > + * cannot be probed correctly from the hard-/firm-ware. > + * > + * Returns: > + * A negative error value or > + * an override value in the range [0, 255] representing 0-100% to be sca= led to > + * the drivers target range. > + */ > +int drm_get_panel_min_brightness_quirk(const struct drm_edid *edid) > +{ > + const struct drm_panel_min_backlight_quirk *quirk; > + size_t i; > + > + if (!IS_ENABLED(CONFIG_DMI)) > + return -ENODATA; > + > + if (!edid) > + return -EINVAL; > + > + for (i =3D 0; i < ARRAY_SIZE(drm_panel_min_backlight_quirks); i++) { > + quirk =3D &drm_panel_min_backlight_quirks[i]; > + > + if (drm_panel_min_backlight_quirk_matches(quirk, edid)) > + return quirk->min_brightness; > + } > + > + return -ENODATA; > +} > +EXPORT_SYMBOL(drm_get_panel_min_brightness_quirk); > + > +MODULE_DESCRIPTION("Quirks for panel backlight overrides"); > +MODULE_LICENSE("GPL"); > diff --git a/include/drm/drm_utils.h b/include/drm/drm_utils.h > index 70775748d243..267711028dd4 100644 > --- a/include/drm/drm_utils.h > +++ b/include/drm/drm_utils.h > @@ -11,9 +11,12 @@ > #define __DRM_UTILS_H__ >=20=20 > #include > +#include Please prefer forward declarations over includes where possible. Here, struct drm_edid; is sufficient. BR, Jani. >=20=20 > int drm_get_panel_orientation_quirk(int width, int height); >=20=20 > +int drm_get_panel_min_brightness_quirk(const struct drm_edid *edid); > + > signed long drm_timeout_abs_to_jiffies(int64_t timeout_nsec); >=20=20 > #endif --=20 Jani Nikula, Intel