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=-3.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 31A06C433DB for ; Fri, 22 Jan 2021 13:02:48 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 E9A2123437 for ; Fri, 22 Jan 2021 13:02:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E9A2123437 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=atomide.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+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=merlin.20170209; h=Sender:Content-Transfer-Encoding: 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-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=/nwjUtoiY3/+Icc+/pRl9a3O4HL4DRJuygCtLBst+hY=; b=YeeC5oflN06dRXD7tTYcPnWoV Qmd/xl1AmnK/6vqyT07RajJ5qWGK6ToMxNKwuwPM+QlcPPSLL9JnmHKfZdqe6g3TI18H+zb5URO7M L4rQyGZB6AF6KF81indd0W+YTzODBVMFqwDZo0Z06joaJQFGq51iVY+Z69iHL7hTG5NEBpHqwYZn4 5tnYjZ0YgwcNUs9VoPD6UrfJyfzShFGJqVt87LnUFrUkCbTTmSgiMVVPxaIzbe1pMLjQyDVipHqFH bkfzjpOtrVviizEz8k4IDgrXoGAVf40i6tpf+JxPlCCrsxO8QAGuBLwXvpu9/IVlZ/HMHQ7QQPswC 4DJMowPzQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l2w3f-00008x-3x; Fri, 22 Jan 2021 13:00:59 +0000 Received: from muru.com ([72.249.23.125]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l2w3Y-00005z-51 for linux-arm-kernel@lists.infradead.org; Fri, 22 Jan 2021 13:00:53 +0000 Received: from atomide.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id E0C6580B3; Fri, 22 Jan 2021 13:00:46 +0000 (UTC) Date: Fri, 22 Jan 2021 15:00:43 +0200 From: Tony Lindgren To: Arnd Bergmann Subject: Re: [PATCH v3 3/5] arm64: dts: ti: Add support for AM642 SoC Message-ID: References: <20210120202532.9011-1-d-gerlach@ti.com> <20210120202532.9011-4-d-gerlach@ti.com> <197af185-d2ea-3c76-d0bf-714485f8f195@ti.com> <20210121174639.jqbvem6b4ozd3six@sterling> <4ee6f005-2eee-42b2-b573-e10602839e1b@ti.com> <20210121183909.pwpboiptqbof2dfu@squint> <2b35fb8b-0477-f66d-bcbd-ad640664a888@ti.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210122_080052_281274_DC198888 X-CRM114-Status: GOOD ( 39.26 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Nishanth Menon , DTML , Vignesh Raghavendra , Arnd Bergmann , Dave Gerlach , Lokesh Vutla , Sekhar Nori , Kishon Vijay Abraham , Rob Herring , Aswath Govindraju , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org * Arnd Bergmann [210122 11:24]: > On Thu, Jan 21, 2021 at 8:57 PM Suman Anna wrote: > > On 1/21/21 12:39 PM, Nishanth Menon wrote: > > > On 12:13-20210121, Suman Anna wrote: > > >> > > >> Hmm, this is kinda counter-intuitive. When I see a dts node, I am expecting the > > > > > > What is counter intutive about a -next branch be tested against > > > linux-next tree? > > > > The -next process is well understood. FWIW, you are not sending your PR against > > -next branch, but against primarily a -rc1 or -rc2 baseline. > > > > As a developer, when I am submitting patches, I am making sure that things are > > functional against the baseline you use. For example, when I split functionality > > into a driver portions and dts portions, I need to make sure both those > > individual pieces boot fine and do not cause regressions, even though for the > > final functionality, you need both. > > > > > > > > > Now, if you want to launch a product with my -next branch - go ahead, I > > > don't intent it for current kernel version - you are on your own. > > > > > > If there is a real risk of upstream next-breaking - speakup with an > > > real example - All I care about is keeping upstream functional and > > > useable. > > > > This is all moot when your own tree doesn't boot properly. In this case, you are > > adding MMC nodes, but yet for a boot test, you are saying use linux-next for the > > nodes that were added or you need additional driver patches (which is not how > > maintainer-level trees are verified). > > > > Arnd, > > Can you please guide us here as to what is expected in general, given that the > > pull-request from Nishanth goes through you, and if there is some pre-existing > > norms around this? > > There are two very different cases to consider, and I'm not sure which one > we have here: > > - When submitting any changes to a working platform, each patch on > a branch that gets merged needs to work incrementally, e.g. a device > tree change merged through the soc tree must never stop a platform > from booting without a patch that gets merged through another branch > in the same merge window, or vice versa. > As an extension of this, I would actually appreciate if we never do > incompatible binding changes at all. If a driver patch enables a new > binding for already supported hardware, a second patch changes > the dts file to use the new binding, and a third patch removes the > original binding, this could still be done without regressions over > multiple merge windows, but it breaks the assumption that a new > kernel can boot with an old dtb (or vice versa). This second one > is a softer requirement, and we can make exceptions for particularly > good reasons, but please explain those in the patch description and > discuss with upstream maintainers before submitting patches that do > this. > > - For a newly added hardware support, having a runtime dependency > on another branch is not a problem, we do that all the time: Adding > a device node for an existing board (or a new board) and the driver > code in another branch is not a regression because each branch > only has incremental changes that improve hardware support, and > it will work as soon as both are merged. > You raised the point about device bindings, which is best addressed > by having one commit that adds the (reviewed) binding document > first, and then have the driver branch and the dts branch based on > the same commit. > > I hope that clarifies the case you are interested in, let me know if I > missed something for the specific case at hand. Hmm and additionally few more mostly obvious things that have helped quite a bit: - Each commit in each topic branch should compile and boot so git bisect works - Each topic branch should be ideally based on -rc1 to leave out dependencies to other branches - Aiming for a working and usable -rc1 is worth the effort in case git bisect is needed for any top branches based on it :) Otherwise you'll be wasting the -rc cycle chasing regressions.. Regards, Tony _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel