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 0717EC4345F for ; Tue, 16 Apr 2024 12:41:56 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7FDF210F4E9; Tue, 16 Apr 2024 12:41:55 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="DGILtrFL"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.10]) by gabe.freedesktop.org (Postfix) with ESMTPS id 5C05110F4E9 for ; Tue, 16 Apr 2024 12:41:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1713271315; x=1744807315; h=from:to:subject:in-reply-to:references:date:message-id: mime-version:content-transfer-encoding; bh=9lm9gLMfdqJDr14H4atP+/9kvfFEhrfD1gfH4rSBl50=; b=DGILtrFLIn56kdihdN+oAaAJlzPEmu4vMDvpt0k83g3iuydfYAmCtfly Z4iL4CU2bVLR6NhTmWLS8WjotJdVK1DS902K7OMklHg20Fi3G6DUQAuVx qLnAyj3Z3Qp7pzomkuh1US7FLEA37ORN1ac/h5U+SkCg+KZWHIzm9cazl paXAk1Jij3LotQvKy9WyvMMALo4DpKat/s0IvpVSPw4syfjL+Z3hK4LSD X1UBBKZFNqJjgjm4YQ20nSRkg7gjS+mn1PvQ3hMEHbjx8sYmFqUKuK4cY MSSr+gvLBWx0rbHsp7R79RhwlS9k3A17ScS9bPsoY/GWNMoTp4dFwzqlX Q==; X-CSE-ConnectionGUID: U0e5NvJyTKOMk7WPK6rSBg== X-CSE-MsgGUID: ehVDnjY5TyuljZ+kT9LA9Q== X-IronPort-AV: E=McAfee;i="6600,9927,11046"; a="20093636" X-IronPort-AV: E=Sophos;i="6.07,206,1708416000"; d="scan'208";a="20093636" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by fmvoesa104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Apr 2024 05:41:54 -0700 X-CSE-ConnectionGUID: FmhN4TmKRqGI1Fpt0CnxRQ== X-CSE-MsgGUID: vtsSGt1WTVqY1zmdZs5sBA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.07,206,1708416000"; d="scan'208";a="45528759" Received: from martakit-mobl.ger.corp.intel.com (HELO localhost) ([10.252.44.100]) by fmviesa002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Apr 2024 05:41:53 -0700 From: Jani Nikula To: =?utf-8?Q?Jos=C3=A9?= Relvas , intel-gfx@lists.freedesktop.org Subject: Re: [REQUEST] Add support for Intel DPST (Display Power Saving Technology) In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <87sezlzqib.fsf@intel.com> Date: Tue, 16 Apr 2024 15:41:50 +0300 Message-ID: <87edb5zdgx.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable 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: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Tue, 16 Apr 2024, Jos=C3=A9 Relvas wrote: > One more question. Some documentation refers to=20 > "OPST (OLED power saving technology)". It's my understanding that this > uses the same hardware blocks and APIs as DPST - only the algorithm > in software is different. Userspace would need a way to distinguish > OLED panels from LCD panels so it can use the right algorithm. Is > there a reliable way of doing this?=20 > On my Thinkpad P1 gen 6, the OLED exposes a standard intel_backlight, > which actually controls the PWM. Afaik, there's no other way of > telling OLED and LCD apart in userspace. The intel_backlight interface can actually control the brightness of the OLED panel using the DPCD interface, not only backlight PWM. It depends on the panel. See intel_dp_aux_backlight.c. (And yes, backlight can be a misnomer here, since OLED does not have a backlight.) I don't actually know the details of OPST, but some OLED panels I've worked with in the past have CABC, or content adaptive brightness control, where all of it is handled internally in the panel. You just tune the aggressiveness or some other mode. BR, Jani. --=20 Jani Nikula, Intel