From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 1E110CAC5AA for ; Thu, 18 Sep 2025 12:44:24 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0FBAA10E898; Thu, 18 Sep 2025 12:44:23 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=collabora.com header.i=@collabora.com header.b="QStIFduX"; dkim-atps=neutral Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) by gabe.freedesktop.org (Postfix) with ESMTPS id A673010E66C; Thu, 18 Sep 2025 08:40:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1758184858; bh=wkdHSWOqeYK7n4RsHjVudEoksMfRdS1NB7ACekPCh0A=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=QStIFduXexoAAzOLAvOJaQI9nVerHdHQ1zMlvFMQxvef1K06itgtq8C/+vG403PME COHLexsulXNL/hGoIoBPReg76vPBLjGzBQB5UtVV70Ts7BrI92mVDOxfS1C0vAMCNO KvSvPD29IK0Wttmxy1KTU9Q41SwWC1WJkOYVEwhETgTQ9VNEutDziL0c4qT3+TX0y8 0BW9BBas5MAWezpj7G7m6/hXB8PgP8gIj+a9KJYEOhSsvn8kYnhRxz7Daf7zvLtz6f aVT4Oc1kbHHKfuwxBePjjXmHrbeL/UAeLJDdz2EgrF84+HbhrEWzsXkhlTHWymyfnt od36Lcc6SjIoQ== Received: from eldfell (unknown [194.136.85.206]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: pq) by bali.collaboradmins.com (Postfix) with ESMTPSA id 0595E17E12C4; Thu, 18 Sep 2025 10:40:56 +0200 (CEST) Date: Thu, 18 Sep 2025 11:40:36 +0300 From: Pekka Paalanen To: Alex Hung Cc: Xaver Hugl , Sebastian Wick , dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, wayland-devel@lists.freedesktop.org, harry.wentland@amd.com, leo.liu@amd.com, ville.syrjala@linux.intel.com, contact@emersion.fr, mwen@igalia.com, jadahl@redhat.com, shashank.sharma@amd.com, agoins@nvidia.com, joshua@froggi.es, mdaenzer@redhat.com, aleixpol@kde.org, victoria@system76.com, daniel@ffwll.ch, uma.shankar@intel.com, quic_naseer@quicinc.com, quic_cbraga@quicinc.com, quic_abhinavk@quicinc.com, marcan@marcan.st, Liviu.Dudau@arm.com, sashamcintosh@google.com, chaitanya.kumar.borah@intel.com, louis.chauvet@bootlin.com, mcanal@igalia.com, nfraprado@collabora.com, Daniel Stone Subject: Re: [PATCH V11 06/47] drm/colorop: Add 1D Curve subtype Message-ID: <20250918114036.454735e9@eldfell> In-Reply-To: <610215a0-50ad-45b8-b60a-a52441619c73@amd.com> References: <20250815035047.3319284-1-alex.hung@amd.com> <20250815035047.3319284-7-alex.hung@amd.com> <4eef4157-cad5-4399-9bc9-c5c2f005d472@amd.com> <20250826120306.618c275f@eldfell> <610215a0-50ad-45b8-b60a-a52441619c73@amd.com> X-Mailer: Claws Mail 4.3.1 (GTK 3.24.49; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: multipart/signed; boundary="Sig_/uzPsFupCAS4ezSX2oPq_XI0"; protocol="application/pgp-signature"; micalg=pgp-sha256 X-Mailman-Approved-At: Thu, 18 Sep 2025 12:44:21 +0000 X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" --Sig_/uzPsFupCAS4ezSX2oPq_XI0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Tue, 16 Sep 2025 17:01:07 -0600 Alex Hung wrote: > On 8/26/25 03:03, Pekka Paalanen wrote: > > On Thu, 21 Aug 2025 11:54:32 -0600 > > Alex Hung wrote: > > =20 > >> On 8/21/25 06:23, Xaver Hugl wrote: =20 > >>>> We user space folks have been convinced at this point that the sRGB = EOTF > >>>> is actually gamma 2.2, and not the piece-wise function. Now, if the > >>>> hardware is actually the piece-wise, then that's what should be expo= sed, > >>>> but I'm a bit unsure if we should do that under the name sRGB EOTF. = =20 > >>> Maybe simply rename the enum string to "sRGB piece-wise EOTF"? In > >>> hindsight, the naming of "srgb" in the Wayland protocol caused a lot > >>> of confusion, it's better to be explicit about it where possible. =20 > >> > >> I will leave this to Harry to comment. He is taking a few days off so I > >> will check with him later. > >> =20 > >=20 > > "sRGB inverse OETF"? > >=20 > > Strictly speaking "sRGB piece-wise EOTF" is not a thing AFAIU. > >=20 > >=20 > > Thanks, > > pq =20 >=20 > If an extension in future after this proposal is merged, can it be GAMMA= =20 > 2.2 to be [DRM_COLOROP_1D_CURVE_GAMMA22] =3D "GAMMA 2.2" so it won't=20 > conflict with current name? >=20 > Meanwhile, do we agree to change "sRGB EOTF" as "sRGB Inverse OETF" as=20 > the following? or do we still want to add "piece-wise"? Hi Alex, since my previous comment, things have muddied further again. FWIW, we intend to remove the use of the name "srgb" transfer function completely from the Wayland protocol as confusing: https://gitlab.freedesktop.org/wayland/wayland-protocols/-/merge_requests/4= 42 I would recommend the KMS UAPI to similarly avoid the term. I would recommend "gamma 2.2" or even "power 2.2" and "compound power 2.4" or such. These names would hopefully not trigger intuition and make people look at the definition harder. Or any other name you can come up with. I agree that "piece-wise sRGB EOTF" would be intuitively clear, but it may provoke people debating what does IEC 61966-2-1 actually define. We've had these kind of discussions for Wayland already, and it was suggested that it is better to define the actual mathematical function in our specification that to leave it for interpretation from standards. For KMS, this should be even easier than for Wayland, because the hardware implements a specific mathematical function regardless of where it might have originated or what it is being used for. Thanks, pq > diff --git a/drivers/gpu/drm/drm_colorop.c b/drivers/gpu/drm/drm_colorop.c > index 1551b86471ce..90a216c0b6ac 100644 > --- a/drivers/gpu/drm/drm_colorop.c > +++ b/drivers/gpu/drm/drm_colorop.c > @@ -71,7 +71,7 @@ static const struct drm_prop_enum_list=20 > drm_colorop_type_enum_list[] =3D { > }; >=20 > static const char * const colorop_curve_1d_type_names[] =3D { > - [DRM_COLOROP_1D_CURVE_SRGB_EOTF] =3D "sRGB EOTF", > + [DRM_COLOROP_1D_CURVE_SRGB_EOTF] =3D "sRGB Inverse OETF", > [DRM_COLOROP_1D_CURVE_SRGB_INV_EOTF] =3D "sRGB Inverse EOTF", > [DRM_COLOROP_1D_CURVE_PQ_125_EOTF] =3D "PQ 125 EOTF", > [DRM_COLOROP_1D_CURVE_PQ_125_INV_EOTF] =3D "PQ 125 Inverse EOTF", > diff --git a/include/drm/drm_colorop.h b/include/drm/drm_colorop.h > index e4250b7d8de8..ce85c52c60c8 100644 > --- a/include/drm/drm_colorop.h > +++ b/include/drm/drm_colorop.h > @@ -43,7 +43,7 @@ enum drm_colorop_curve_1d_type { > /** > * @DRM_COLOROP_1D_CURVE_SRGB_EOTF: > * > - * enum string "sRGB EOTF" > + * enum string "sRGB Inverse OETF" > * > * sRGB piece-wise electro-optical transfer function. Transfer > * characteristics as defined by IEC 61966-2-1 sRGB. 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