From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout-03.galae.net (smtpout-03.galae.net [185.246.85.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7C741396B6B; Wed, 8 Apr 2026 07:55:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.246.85.4 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775634948; cv=none; b=DV/f+LI70dhot7OMdYcuFM6iW+rdI8hFPTyC2dVPXkurgwyW4zLy7C9GaI0En14qwTJjRs40TabksJpKgAIidvnQlMn8TbJs695d5DN4MPFzFmPrqby8Jtj/1YAZy5uPgWeUc/riVO/dL+IXoK6d4+rVpQveARl0n+tvsCCX2QM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775634948; c=relaxed/simple; bh=AH6dJigQs5hz84A7MorI6yrN4/3IGUQSRRNzsp2M+jc=; h=Mime-Version:Content-Type:Date:Message-Id:From:Subject:Cc:To: References:In-Reply-To; b=aUYdSqz7XfRtIkG90ANbzFEGFVjkknHq/rWkLcguhrYvMPnGF5AxMFPl0siGmD67jmPtB4brqMyUs+cHcj537FCbJb1apR1plfdz9uy0ig0STabqp13vErbvqt/o+hZxl57vhDWaCects4I+1GhnqPYAJ9kItuHs9FvZJfawb9Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=ZezyUPUb; arc=none smtp.client-ip=185.246.85.4 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="ZezyUPUb" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-03.galae.net (Postfix) with ESMTPS id DD9AC4E42977; Wed, 8 Apr 2026 07:55:43 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id B1963603CB; Wed, 8 Apr 2026 07:55:43 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 1C65D104503D0; Wed, 8 Apr 2026 09:55:39 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1775634942; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=rvnKg1xMJhGiVQnrTAtZ8gZFRNiU/MpXI3BNFhAd8Ck=; b=ZezyUPUb0hRfNKObxlk3XBRzRpnx/sdVAvENgYporqPvlkuEv3Wwk3WFSaU2+QkgaAhScv iJKh/iNOZbFZr0wjBtSDBC/aN/g88OlksUTPfvonkovBxkmdCvtGKU/I06lDNEY3zFxdo/ C+L6b7wG+1npaTGcIzlshu22I/ezzAa5NkRa9DKy1JPb/FmCnREalQpIH+ioVMALL86seE plPR37RHiiwSvxbB4vbxoRRAYCo3N/uu2oVLr0V1VznsrhG2nJ9XPa+2BtNVnmfERFGjlO izeosxBtFv2W1lnyZ+jWqdyMM8V8E3tvo0yXeFz/TYcyNI2A7xXNc/T4mHzq6w== Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Wed, 08 Apr 2026 09:55:37 +0200 Message-Id: From: "Luca Ceresoli" Subject: Re: [RFC PATCH 15/15] Introduce v18 dtb version Cc: "David Gibson" , "Rob Herring" , "Krzysztof Kozlowski" , "Conor Dooley" , "Ayush Singh" , "Geert Uytterhoeven" , , , , , "Hui Pu" , "Ian Ray" , "Thomas Petazzoni" To: "Herve Codina" X-Mailer: aerc 0.20.1 References: <20260210173349.636766-1-herve.codina@bootlin.com> <20260210173349.636766-16-herve.codina@bootlin.com> <20260407184423.3060f1cd@bootlin.com> In-Reply-To: <20260407184423.3060f1cd@bootlin.com> X-Last-TLS-Session-Version: TLSv1.3 On Tue Apr 7, 2026 at 6:44 PM CEST, Herve Codina wrote: > Hi Luca, > > On Wed, 01 Apr 2026 17:19:09 +0200 > "Luca Ceresoli" wrote: > >> On Tue Feb 10, 2026 at 6:33 PM CET, Herve Codina wrote: >> > This v18 version will add support for >> > - Structured tags. >> > Those tags value definition will allow old libfdt, dtc and other >> > tools to skip unknown tags if encountered in future dtb version. >> >> "old" seems to imply that versions released before today will be able to >> wkip unknown tags. I think this should be clarified along the lines of: >> >> libfdt, dtc and other tools implementing version v18 will be able to w= kip >> unknown tags in dtbs generated with later versions of dtc > > Yes, I will add this clarification in the next iteration. > >> >> > - dt_flags header field. >> > For now this flag field is set to 0. It is a placeholder for futur= e >> > dtb version and could be used to store some dtb related informatio= n >> > such as the kind of dtb. >> >> Is this intended for DT addons? >> >> You may mention a realistiv use case here. > > Intended, maybe not. Used by addons, yes, for sure. > > What do you think if I add the following: > For instance, the future addons format will use this field to > clearly identify that the dtb is an addon dtb. This clarifies a lot to me, so I think it can be added to the commit message. >> > Compared to previous version, it is worth noting that the dtb is not >> ^ >> "dtb version" >> >> > downgrade for all modification but only when unknown tags are removed >> ^ >> downgraded for any >> >> >> > due a property modification. >> ^ >> "due to a ..." >> >> I'm not sure I got what you mean by the initial "Compared to previous >> version". Version(s) of what? >> >> If I just remove those 4 words the sentence seems OK to me BTW. > > Is the following clearer? > > It is worth noting that with this v18 version, the dtb version is not > downgraded for any modification but only when unknown tags are remove= d > due to a property modification. In v17 or older version any modificat= ion > led to a dtb version downgrade. Yes, totally clear now, thanks! Luca -- Luca Ceresoli, Bootlin Embedded Linux and Kernel engineering https://bootlin.com