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 13C8DC433FE for ; Mon, 3 Oct 2022 10:32:40 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7797A10E2E4; Mon, 3 Oct 2022 10:32:30 +0000 (UTC) Received: from mail-lf1-x12a.google.com (mail-lf1-x12a.google.com [IPv6:2a00:1450:4864:20::12a]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0CEF210E24A; Mon, 3 Oct 2022 10:32:27 +0000 (UTC) Received: by mail-lf1-x12a.google.com with SMTP id k10so15922610lfm.4; Mon, 03 Oct 2022 03:32:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:message-id:subject:cc:to:from :date:from:to:cc:subject:date; bh=GDaIoGT7JIsoOWeW0LenQTO0aul26961IrOBNUNTmEE=; b=hiacyR2cfOlAQqt8WmjjJYbU9MsLy++EJ1pjpIZeGhehD4EMZUJ4ZoJtuW1NHLcWLC +RENyWxyN2ePpAlbzrKyI+VCmbcWbzlRVa7IiRNazh+CvpUS5a46c1JC5vVzISVRUFXb mKm9jWTDkavKvKlgbD/ItdxHiBZVRvungmkK4GmAahBKvzHQTwcIaNCwb8cg87WObg70 PcyzwO+Gn1jlEGEXPgn5YmgjIl5+VuXMktGkb/W4yj/fIeiUQKhpF25PmvLjxmfUrQP5 73WHEobKao7w6fe9dPnnrDC1GqCJT5dAsmrSqliLuSHMq/Ttn7hIT3X8OIELbG7Y1h5T SN5w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=mime-version:references:in-reply-to:message-id:subject:cc:to:from :date:x-gm-message-state:from:to:cc:subject:date; bh=GDaIoGT7JIsoOWeW0LenQTO0aul26961IrOBNUNTmEE=; b=if4bhts3tBbE8YTEnAWdp5k1uaKY1CGOGPdb15H2uYH19jLaUk0TT83i3l/yUWIeUw KfVsCFZ3IrXxyGDbDUz+JZIOPgW7YDZTiCsxFtm1MVynbTEjpgQkA72cvqzh4Uairf/q twCIWnAupcdCItY3bG60eFuC3FSVnKbaL532sEUM9HxlGOEsN6Jlx6vd1To+B/TbSs0Y qWjBgItJ1LmJYkZjX+VwGXPOxL1BB/naq3g2n4IXRkYtHJyfohZsGBJha+gaaUNyz14x wevxdHZvVijCm8xShvPcQAT5wzus2LNEqlAk1CKx9hmq5leJ0YllugWbD+j3IkmONyxT EUNw== X-Gm-Message-State: ACrzQf2m2ZnKNnXgMwup5T0SFEKWoy0B7CayLj7XWbrkBi7LDjx7a7g8 s9LZtFSSDHFbUOCRlBpE/X8= X-Google-Smtp-Source: AMsMyM52BRFIuhBqhoICF1XSuRe8FtxZvtb7rPqWWuFpQm3UIgLxcyv10uv8EkfAhuNHRQKp2fPDag== X-Received: by 2002:a05:6512:31d5:b0:498:f3dc:dd2 with SMTP id j21-20020a05651231d500b00498f3dc0dd2mr6633185lfe.101.1664793145146; Mon, 03 Oct 2022 03:32:25 -0700 (PDT) Received: from eldfell ([194.136.85.206]) by smtp.gmail.com with ESMTPSA id c18-20020a056512105200b00497ad8e6d07sm1401745lfb.222.2022.10.03.03.32.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Oct 2022 03:32:24 -0700 (PDT) Date: Mon, 3 Oct 2022 13:32:22 +0300 From: Pekka Paalanen To: Hans de Goede Subject: Re: [RFC v2] drm/kms: control display brightness through drm_connector properties Message-ID: <20221003133222.7f34862f@eldfell> In-Reply-To: <44df4468-955b-0226-67e7-89467291d38f@redhat.com> References: <878rm3zuge.fsf@intel.com> <20220930103956.1c3df79e@eldfell> <20220930182652.4ea10013@eldfell> <44df4468-955b-0226-67e7-89467291d38f@redhat.com> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: multipart/signed; boundary="Sig_/Y_N=Mebig8zOE0MefvI6YCr"; protocol="application/pgp-signature"; micalg=pgp-sha256 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sebastian Wick , Christoph Grenz , Martin Roukala , "dri-devel@lists.freedesktop.org" , wayland , Yusuf Khan Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" --Sig_/Y_N=Mebig8zOE0MefvI6YCr Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Mon, 3 Oct 2022 11:44:56 +0200 Hans de Goede wrote: > One example mentioned here is that laptops with Intel integrated > graphics may have some "perceived brightness" mapping table > in their Video BIOS Tables (VBT) it would be interesting to use > this and to export the curve coming from that to userspace as > extra information (including allow userspace to write it). > Since in this case (unlike many other cases) at least this > curve is done in the kernel I guess we can then also add a boolean > property to disable the curve (making it linear) in case that > is helpful for HDR scenarios. Hi Hans, what if you would export that curve to userspace and not apply it in the kernel, aside from the min-luminance=3D0 offset? I'm not sure if that was your intention, I didn't see it clearly said. Of course this can be only about curves that are supposed to be applied by the OS and not applied in firmware or hardware. Call it "software curve"? Let userspace apply that curve if it happens to exist. Then, if we get some other definition replacing that curve on some hardware, the kernel could just expose the other thing as a new thing, and the old curve API would not be interfering. Userspace that does not understand the new thing (and the old curve property is not populated) would still be able to control the brightness, just not in as pleasant way. It would also make using a custom curve a completely userspace thing with no need for the kernel to support overwriting it. Thanks, pq --Sig_/Y_N=Mebig8zOE0MefvI6YCr Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEJQjwWQChkWOYOIONI1/ltBGqqqcFAmM6ujYACgkQI1/ltBGq qqeY5Q/9ELYd/Jr7PMSxivgZlgFDIRRSMfEuDbO7Q64hjorSDQ+dTgXCLFmiGuHR ChABp2ulCoUEG48nuHWXEpG1qsR0bcp7HqwzaSzeZAQc8j/M7RBF6O8YnF1yLWU7 /b3Otpq7v0Yut8xy4J/wVQHJ2eDwARh/5l4leaxw4+D8NlObTing8oF+X4Byt9tq Qz2wBiLtSQ5U7d5FhZaF+ukCLv/IFKTu0uQAnDYvTGaywOa7A4KW7GFmZSU5I36V WA9nB+2ob2m4lmofhs+dJ6SwSsDCLwwRm10HCpwaTytuBHL3BzPqtJFmf/HlDOHX CfPeu0ff1mcez9lN+MTAh6cyEYZvkWVtPl/Pxd2Z2pYYC09PyUDeniLBh0v1O9pA RwQY05UqU9X04xxsl0wOKLsT9K1WtFF2s2R0GsweL5Em85fGTF+ctC45IklxT/xc 5PW2dnSeji0vlYfZOx4VPQatd9DSUb+ufPz4RBV0Xc9EPVUivrBOMIdbxESYqF/P eOxsmQ9LD5EclRM3vmBsBF55z/Jtfa8Pb9DNTUrFU7GZwxX1mg43OVCDIfT536jI V9Reik8HHF7BI9WQfTx3k+TiSfCiYPCWQq6JP0f6Krv521yHqtoK5/Tp+X0mXB7p ieuuzkbi2Q2iXCCSB6Bfn0pbDKATfMEa8pLTFOqjMo/vhe1t/kE= =3lTR -----END PGP SIGNATURE----- --Sig_/Y_N=Mebig8zOE0MefvI6YCr--