From nobody Fri Dec 19 18:31:30 2025 Received: from todd.t-8ch.de (todd.t-8ch.de [159.69.126.157]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5CD6B42A97; Sat, 24 Aug 2024 18:34:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.69.126.157 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724524479; cv=none; b=H6WRpHEaaVoMXdCQ/UTT7/zF4/8FdgKMDF5lqHcm6bCV7diG8QaXeFzZtzdUs0yL7PPSlUxhCwpnzpgty+aSZpobz710HGHpvTNe7XZpjLEzpy/JrwZ3ImgOr988zrg+LAOjd2S3r0Soo9R//2UoFpoS7JZPrM0DjGUmCFIriso= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724524479; c=relaxed/simple; bh=jPTjo8xHszfHKo7sgVPOL9TrpX9WTP+c7wzcRqjMglI=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=L7m/HdcKeIdvmM/FpgJ4fgk0cr2gRaEF7IZVeuuYHlLJaY2ZW/MKus5BrZMneaS2n7EGDlp7ptpdnTKvdB6c7G8/9nnaSGdiUi06i/l6d5q3R4krBokQf3IVwd+6i2kf2oRU4d0TGXkv71MWp7jjIE4kia0+yU5KylQqUghBAEc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=weissschuh.net; spf=pass smtp.mailfrom=weissschuh.net; dkim=pass (1024-bit key) header.d=weissschuh.net header.i=@weissschuh.net header.b=cireCPew; arc=none smtp.client-ip=159.69.126.157 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=weissschuh.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=weissschuh.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=weissschuh.net header.i=@weissschuh.net header.b="cireCPew" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=weissschuh.net; s=mail; t=1724524474; bh=jPTjo8xHszfHKo7sgVPOL9TrpX9WTP+c7wzcRqjMglI=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=cireCPew2EtzY8gJ16x3cRSM4QRjWkOE3BkIqskFFXZZWdJebxj2H7EHGTmdyxz+n XaN8QNsINVUO80tk5XZaXZCofpHR0EIIPIv2xnKoeQn8W0kJp5G8B6VIqZ+T9YqKrj Qa2EZUKmv1iSBfpPXCJw3cKlg/4k2XlgE7ioFe2E= From: =?utf-8?q?Thomas_Wei=C3=9Fschuh?= Date: Sat, 24 Aug 2024 20:33:54 +0200 Subject: [PATCH v6 1/4] drm: Add panel backlight quirks Precedence: bulk X-Mailing-List: linux-kernel@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 Message-Id: <20240824-amdgpu-min-backlight-quirk-v6-1-1ed776a17fb3@weissschuh.net> References: <20240824-amdgpu-min-backlight-quirk-v6-0-1ed776a17fb3@weissschuh.net> In-Reply-To: <20240824-amdgpu-min-backlight-quirk-v6-0-1ed776a17fb3@weissschuh.net> To: Alex Deucher , =?utf-8?q?Christian_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 , Jani Nikula , 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, =?utf-8?q?Thomas_Wei=C3=9Fschuh?= X-Mailer: b4 0.14.1 X-Developer-Signature: v=1; a=ed25519-sha256; t=1724524474; l=4991; i=linux@weissschuh.net; s=20221212; h=from:subject:message-id; bh=jPTjo8xHszfHKo7sgVPOL9TrpX9WTP+c7wzcRqjMglI=; b=GvmUKTrjus/ulbBqwnDfwuFvjdkFTYj3oL5MAAFXHLvhMy/7bLvwYdulBAheGb+JFahDvYvL1 dTrGKRO8A20DSoM8PTZtpzA5dJ9uw8Z9ZRQxmY+aDXIqymSOWVL19XT X-Developer-Key: i=linux@weissschuh.net; a=ed25519; pk=KcycQgFPX2wGR5azS7RhpBqedglOZVgRPfdFSPB1LNw= Panels using a PWM-controlled backlight source 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 Tested-by: Dustin L. Howett Reviewed-by: Mario Limonciello --- 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 | 70 ++++++++++++++++++++++++= ++++ include/drm/drm_utils.h | 4 ++ 5 files changed, 82 insertions(+) diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-= 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 +.. 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 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 +# 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 obj-$(CONFIG_DRM_PANEL_ORIENTATION_QUIRKS) +=3D drm_panel_orientation_quir= ks.o +obj-$(CONFIG_DRM_PANEL_BACKLIGHT_QUIRKS) +=3D drm_panel_backlight_quirks.o =20 # # Memory-management helpers diff --git a/drivers/gpu/drm/drm_panel_backlight_quirks.c b/drivers/gpu/drm= /drm_panel_backlight_quirks.c new file mode 100644 index 000000000000..6b8bbed77c7f --- /dev/null +++ b/drivers/gpu/drm/drm_panel_backlight_quirks.c @@ -0,0 +1,70 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#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_backlight_= quirks[] =3D { +}; + +static bool drm_panel_min_backlight_quirk_matches(const struct drm_panel_m= in_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 l= evel 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 th= is + * 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 scale= d 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..15fa9b6865f4 100644 --- a/include/drm/drm_utils.h +++ b/include/drm/drm_utils.h @@ -12,8 +12,12 @@ =20 #include =20 +struct drm_edid; + int drm_get_panel_orientation_quirk(int width, int height); =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 #endif --=20 2.46.0