From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [PATCH RESEND v2 08/12] dt-bindings: add binding for generic eDP panel Date: Mon, 4 Feb 2019 17:27:19 +0100 Message-ID: <20190204162719.GC25476@ulmo> References: <20190203185501.8958-1-anarsoul@gmail.com> <20190203185501.8958-9-anarsoul@gmail.com> <20190204074350.GC16448@ulmo> <20190204082353.GE19087@ulmo> Reply-To: thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Pk6IbRAofICFmK5e" Return-path: Sender: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org Content-Disposition: inline In-Reply-To: List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: Vasily Khoruzhick Cc: David Airlie , Daniel Vetter , Rob Herring , Mark Rutland , Maxime Ripard , Chen-Yu Tsai , Archit Taneja , Andrzej Hajda , Laurent Pinchart , Icenowy Zheng , Sean Paul , dri-devel , devicetree , arm-linux , linux-sunxi List-Id: devicetree@vger.kernel.org --Pk6IbRAofICFmK5e Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline On Mon, Feb 04, 2019 at 08:11:05AM -0800, Vasily Khoruzhick wrote: > On Mon, Feb 4, 2019 at 12:24 AM Thierry Reding wrote: > > > > > > Pinebook used several 768p panels that have slightly different timings > > > and recent batch uses 1080p panel. > > > > > > What panel descriptor should I use as fallback? > > > > You don't use panel descriptors as fallback. The simple-panel driver > > will bind to a panel device and use the corresponding descriptor. If > > your device tree contains the correct information, the descriptor is > > correct for the panel you have. > > > > In other words you need to ensure that you have the correct panel in > > device tree for the board that you're using. This is exactly the same > > thing as for other devices. > > > > One way to to this is to have separate device trees for each variant > > of the board that you want to support. Another variant may be to have > > a common device tree and then have some early firmware update the DTB > > with the correct panel information. > > That defeats the purpose of using eDP panels. Panel can identify > itself and report what timings it supports. > > If we use separate DTBs then users will have to figure out what panel > is installed in their hardware and use appropriate software image - > that's something I'd like to avoid. > > I can add a descriptor for something like "pinebook eDP panel" if it > works for you, but it won't have any display timings in it. I'd like to point you to this: http://sietch-tagr.blogspot.com/2016/04/display-panels-are-not-special.html it addresses some of your questions. Hopefully that will also help you understand that this isn't only about display timings. Thierry --Pk6IbRAofICFmK5e-- 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 X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED,DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 18210C282C4 for ; Mon, 4 Feb 2019 16:27:47 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CCB2D2083B for ; Mon, 4 Feb 2019 16:27:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="AUg5gMbD"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="IjeerCXS" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CCB2D2083B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type:Cc: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: In-Reply-To:MIME-Version:References:Message-ID:Subject:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=A+Z6ARtJ/QEnTbvxgVH5Sr28amGKFoyAuxVDdN6duLI=; b=AUg5gMbDDZP3i793sJB9OCuPx Q4XtH/FlsHpXYrfyqz1nSmSLFmdCkhNkJZiyer2r4Om3MR2roP/zOYZKCLB3aG6oSISkElha1zkqD AEFLAIzzYQ85aDE+A9Ga1U2Gec3ZuNu+z02aYi5O1zfnWf8p3rYrbnQ9guPDzJGniZ8dhcXFDhHxa NHI0rXfoYwQoRpkAno1LYy4QsZxNxxGyLiTUV+mqNx+qqPeAOoZMYyQU0UbjteRP61jY/B0r/PJ9t RlH62WSrj0QIOwanTcUs7lpsIX9tOZN6Kn9pMmRNPZHQah7u1zk6Rdp21l88t4ZipvQNygjE1zfGJ qYbTooQiQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gqh5y-0001kh-EO; Mon, 04 Feb 2019 16:27:42 +0000 Received: from mail-wm1-x342.google.com ([2a00:1450:4864:20::342]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gqh5f-0001R1-FJ for linux-arm-kernel@lists.infradead.org; Mon, 04 Feb 2019 16:27:27 +0000 Received: by mail-wm1-x342.google.com with SMTP id y185so10476059wmd.1 for ; Mon, 04 Feb 2019 08:27:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=Ei/F7ERTHjxrPH6rDXq+aZc48wQjGCH/Jl9BdlcMZiU=; b=IjeerCXS2yFzhk37uxdVa5MQMJNUE0lZsoKFN6Zp8ysVrcvX8aoceOtvMQMdrGkGvN 6ipTT3mgkz6Gt9j2cK1HA2KDVhqRDqakCWfslKZnyQXuuncHRNBMe/R97fe4/1O7ZEn8 y6o9kl6da7Ehm9Icg7Je3DQbqayd3vrQkF/SmKHmWERIiMppYxYhjVl60oS/b6oDzi0b 8BhDEbSzHtD071ZqwJvQaKqZmmUjcj2FopybSmhyhbx4nXcupu/LBbHKu7GtWihjLmCG Yj8zHntj911tnLEVGeIeT/+WLEAVYuPkBZcru59ozh7slrTRlp8U4JPMrCpZv2h10yHV TQbQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=Ei/F7ERTHjxrPH6rDXq+aZc48wQjGCH/Jl9BdlcMZiU=; b=pE345dgW/6pywc+VH9cu2XRlISOSUhnm3GkREjjHLEZvOnIBh24W5VYhd4DJK1QjbB brOdrOrxeod7KeMG5lOZ+UGk/sR++m2GJC4zvmmC3xQ5t/pYqmfiCCXXJERj5aw03U9u P3DJq3kpCVtZvsZzW59RkOmscnO6MnA+AMhlodl/urP2hc1mVVfj18ZXMhxKPF/CS1+X f/dc45+Qq9VJEjLGOjoPIfYIPTtmahwXRaeru0xoD9NwJMJ4N4kz4IfCub2Rk2cWi2dr xoeBVBauCzZh2LbLYZU0xrVkLkmpGrncGMF7rcLEV3n5R4eY8aZo/foYBtl+oACWNqJ5 AtFg== X-Gm-Message-State: AHQUAuZhWG+yx8zu63NW/QtpvQ9ZCV47EH6/LW5UIGbSzIyaT81VbJJt 4YMhW83Ls7ibXkUBRNEy8xg= X-Google-Smtp-Source: AHgI3IYYk7NT8LDTkTrgjqEtDsrmNIjpoWqbv/5utRiENO5w/NV0N23JthYI1PHup5QxHjAed3vNNA== X-Received: by 2002:a1c:790c:: with SMTP id l12mr144988wme.11.1549297641280; Mon, 04 Feb 2019 08:27:21 -0800 (PST) Received: from localhost (pD9E51040.dip0.t-ipconnect.de. [217.229.16.64]) by smtp.gmail.com with ESMTPSA id l21sm7334837wmh.29.2019.02.04.08.27.20 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 04 Feb 2019 08:27:20 -0800 (PST) Date: Mon, 4 Feb 2019 17:27:19 +0100 From: Thierry Reding To: Vasily Khoruzhick Subject: Re: [PATCH RESEND v2 08/12] dt-bindings: add binding for generic eDP panel Message-ID: <20190204162719.GC25476@ulmo> References: <20190203185501.8958-1-anarsoul@gmail.com> <20190203185501.8958-9-anarsoul@gmail.com> <20190204074350.GC16448@ulmo> <20190204082353.GE19087@ulmo> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190204_082723_842368_9E89752B X-CRM114-Status: GOOD ( 20.86 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , devicetree , Archit Taneja , Andrzej Hajda , David Airlie , linux-sunxi , dri-devel , Maxime Ripard , Chen-Yu Tsai , Rob Herring , Sean Paul , Laurent Pinchart , Daniel Vetter , arm-linux , Icenowy Zheng Content-Type: multipart/mixed; boundary="===============4290618962981893961==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============4290618962981893961== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Pk6IbRAofICFmK5e" Content-Disposition: inline --Pk6IbRAofICFmK5e Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Feb 04, 2019 at 08:11:05AM -0800, Vasily Khoruzhick wrote: > On Mon, Feb 4, 2019 at 12:24 AM Thierry Reding = wrote: > > > > > > Pinebook used several 768p panels that have slightly different timings > > > and recent batch uses 1080p panel. > > > > > > What panel descriptor should I use as fallback? > > > > You don't use panel descriptors as fallback. The simple-panel driver > > will bind to a panel device and use the corresponding descriptor. If > > your device tree contains the correct information, the descriptor is > > correct for the panel you have. > > > > In other words you need to ensure that you have the correct panel in > > device tree for the board that you're using. This is exactly the same > > thing as for other devices. > > > > One way to to this is to have separate device trees for each variant > > of the board that you want to support. Another variant may be to have > > a common device tree and then have some early firmware update the DTB > > with the correct panel information. >=20 > That defeats the purpose of using eDP panels. Panel can identify > itself and report what timings it supports. >=20 > If we use separate DTBs then users will have to figure out what panel > is installed in their hardware and use appropriate software image - > that's something I'd like to avoid. >=20 > I can add a descriptor for something like "pinebook eDP panel" if it > works for you, but it won't have any display timings in it. I'd like to point you to this: http://sietch-tagr.blogspot.com/2016/04/display-panels-are-not-special.html it addresses some of your questions. Hopefully that will also help you understand that this isn't only about display timings. Thierry --Pk6IbRAofICFmK5e Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEiOrDCAFJzPfAjcif3SOs138+s6EFAlxYZ+cACgkQ3SOs138+ s6HKnw//SPcp61RCvf+9XPzSxlnYUALPXt+A0njrwrJ/dUYVkEOp6LFWRX6DJQTC Ix5QhTCgfOvcz/rvd4yN8p1qp+/VBpUob2/4dMkB4He43CXqlOzRhZ9pYsRZ4dcK Ei8SjSzoBMy74hMspeZ4Hd12/6JkOEgBRH3tyxCbfGg98F8x4gk07nVb1pKQuQlb 7zdEBH+DaAiSphKOn8DZgAPaxLIRm9ELod1zppWmfDq0CvyxEZDV3R4z23O/m6yH sMfDf/kjfDxx2X8RJ85SPzSJh4yTFUNo0zyNDFQ3xxWbt7c167f5C5+4zW0cSIZO MTRH12C6bSKz7cbI7aGu7pXAsFw1gMgc/WikjQuRV1xJkqChxO2UNnlL90hMdXXQ qSATNkfo3HUkIrOS1AiDzqwG5Sr/tvb+H0ETZxQZ9YwI2ckMwYVWIkMbm6ogjMwx UIbUyFPBIJsNX6u6b+3AYJVQqAFPCdU5U8+YxFxssKVzsT0ILG0WMPa9f9miHcx9 jTZnWwcJOVxFCvL1x/GcjMJ/DW5boNR8K3zGLN2bxTWJwpOC+yt0CzsKSqPJxJYl xuY25Zpy/IXi7vRpJUKhrYv3Iz+hnYzFJE3UseCdiW7ZAfOmiUuRLVAlp1AZForx xi4Y82H8FCh15dpO0iiWlumEqMmMK0e/9Fdl6TThKMMjsZLJ6MM= =aXpn -----END PGP SIGNATURE----- --Pk6IbRAofICFmK5e-- --===============4290618962981893961== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel --===============4290618962981893961==--