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 23FFCECAAD5 for ; Mon, 12 Sep 2022 08:44:59 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E747B10E139; Mon, 12 Sep 2022 08:44:50 +0000 (UTC) Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7CDD210E139; Mon, 12 Sep 2022 08:44:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1662972283; x=1694508283; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version:content-transfer-encoding; bh=QskuECXvIQDZopSnldJAGVX2vYRzDDH6HfLyqq9sciA=; b=DwLG/LBTNfZKDFW6R2sY4p+iohfnRn9s9PiofJAsaLHd4WOb8ZA1cExs SvZEuydC0i5rJT6la9SJ0NLWvg9oWMpGwjbvqNlgTDOPkjl1Narr20oJg rdYe6rLsVndoNGbs+Dcaq6q/e90Bb1kh4S3RTHDdYYalvGudhXkdP7zgA Fp62+Tg2DdIg48wVCRwEWiOjVfFSsKdWK9Kj1ihcSN4pVD4fRnYVv0+RS irzQcY/1xKiFxuHvGz0K2OAXX4AVJ1hn50GGGDmydJp5rESpVee4oPMcQ tSAaKfIMjLEd8NxxL1HLWzqtXl67j1R8X9HsuxPyG+Eggsaeeb2yFGMel w==; X-IronPort-AV: E=McAfee;i="6500,9779,10467"; a="324045278" X-IronPort-AV: E=Sophos;i="5.93,308,1654585200"; d="scan'208";a="324045278" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Sep 2022 01:44:42 -0700 X-IronPort-AV: E=Sophos;i="5.93,308,1654585200"; d="scan'208";a="678000152" Received: from abijaz-mobl.ger.corp.intel.com (HELO localhost) ([10.252.58.140]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Sep 2022 01:44:40 -0700 From: Jani Nikula To: =?utf-8?Q?Aur=C3=A9lien?= , Rodrigo Vivi , Hans de Goede , Lyude , dri-devel@lists.freedesktop.org In-Reply-To: <115b5a5ebddcd268ee5f7688400448a2@ap2c.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <878rms7emr.fsf@intel.com> <183219aab00.2890.be34037ad6564a4fe81285fd91a8f407@ap2c.com> <115b5a5ebddcd268ee5f7688400448a2@ap2c.com> Date: Mon, 12 Sep 2022 11:44:37 +0300 Message-ID: <87zgf556dm.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Intel-gfx] Developing a new backlight driver for specific OLED screen X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Fri, 09 Sep 2022, "Aur=C3=A9lien" wrote: > But since this display is independent from the GPU i didn't want to > link both code. If it's eDP and uses some proprietary DPCD brightness control mechanism, I think in practice it usually is somewhat dependent on the GPU. (OTOH I realize you don't mention eDP. If it's not eDP, DDC/CI is the more likely way to control brightness than DPCD.) > For sure. It's an OLED display. Thus there is no backlight. It uses > specific registers to control the brightness of the screen. As Lyude said, we have a bunch of "backlight" terminology for historical reasons, but basically the DP aux, or DPCD, brightness control is mostly agnostic to the display technology. > Unfortunately I guess the mechanism is not shared with many OLED > displays... Do you have a spec for it? How does it differ from the VESA eDP DPCD brightness control? BR, Jani. --=20 Jani Nikula, Intel Open Source Graphics Center