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=-10.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 03BF4C433DB for ; Fri, 29 Jan 2021 01:56:45 +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 8305664DF1 for ; Fri, 29 Jan 2021 01:56:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8305664DF1 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=hisilicon.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:References:Subject:To:MIME-Version:From: Date:Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=VhenXLuPbrUhfNWUPcL583Buyvn8bvQIOPhkJpBONZY=; b=F7ZClDdDx20o+q8ZQeKbBeq/o c0lJv2AoUmk1iQr0ItogtqcWr/zGpibSLFjTVeTvHmTUcgjjxvMsuKxl/cyWWirnW7EckdPzj/4q6 hhSA3pMEtKhv7NXYxrWNJEjtv0yndprUxdQ8/KJE4+ndBAn4PlNqX29ughf43/l/RlQvzFjfo2Y/m oqbISg3JE+IfJEWK+pu3vruCGGTvHswdhmWWcReng2Vlzo1+DwvwkQSB9Gd83rN5xwvRiSBiIBBot n13OSqNC1lOMFykTvu9jl0jnJL7aDzS6fYQPX+NsWRcYX5BThCsKbK4ExSE1Ue6R3W+ZZDdS8JjFe pMwO/PNrg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l5J0V-0002qB-1m; Fri, 29 Jan 2021 01:55:31 +0000 Received: from szxga06-in.huawei.com ([45.249.212.32]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l5J0R-0002oS-Mx for linux-arm-kernel@lists.infradead.org; Fri, 29 Jan 2021 01:55:29 +0000 Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4DRgPT6BHQzjDFw; Fri, 29 Jan 2021 09:54:21 +0800 (CST) Received: from [10.40.166.221] (10.40.166.221) by DGGEMS404-HUB.china.huawei.com (10.3.19.204) with Microsoft SMTP Server id 14.3.498.0; Fri, 29 Jan 2021 09:55:11 +0800 Message-ID: <60136AFF.5080204@hisilicon.com> Date: Fri, 29 Jan 2021 09:55:11 +0800 From: Wei Xu User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Arnd Bergmann Subject: Re: [PATCH v3 2/4] arm64: dts: correct vendor prefix hisi to hisilicon References: <20201208124641.1787-1-thunder.leizhen@huawei.com> <20201208124641.1787-3-thunder.leizhen@huawei.com> <6010B6DE.4060202@hisilicon.com> <60135EBA.5040803@hisilicon.com> In-Reply-To: <60135EBA.5040803@hisilicon.com> X-Originating-IP: [10.40.166.221] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210128_205528_238832_134F776E X-CRM114-Status: GOOD ( 23.18 ) 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: devicetree , Mauro Carvalho Chehab , Chen Feng , Manivannan Sadhasivam , linux-kernel , Rob Herring , Philipp Zabel , Zhen Lei , Zhangfei Gao , linux-arm-kernel 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 Hi Arnd, On 2021/1/29 9:02, Wei Xu wrote: > Hi Arnd, > > On 2021/1/28 22:08, Arnd Bergmann wrote: >> On Wed, Jan 27, 2021 at 1:42 AM Wei Xu wrote: >>> On 2021/1/27 6:23, Arnd Bergmann wrote: >>>> On Tue, Dec 8, 2020 at 1:46 PM Zhen Lei wrote: >>>>> >>>>> The vendor prefix of "Hisilicon Limited" is "hisilicon", it is clearly >>>>> stated in "vendor-prefixes.yaml". >>>>> >>>>> Fixes: 35ca8168133c ("arm64: dts: Add dts files for Hisilicon Hi3660 SoC") >>>>> Fixes: dd8c7b78c11b ("arm64: dts: Add devicetree for Hisilicon Hi3670 SoC") >>>>> Signed-off-by: Zhen Lei >>>>> Cc: Chen Feng >>>>> Cc: Manivannan Sadhasivam >>>> >>>> I see this change in the pull request I got, but I'm a bit worried about the >>>> incompatible binding change. Wouldn't the correct path forward be to >>>> list both the correct and the incorrect properties, both in the dts file >>>> and in the driver that interprets the properties? >>> >>> Thanks for the comment! >>> The reset driver will look for "hisilicon" firstly and fall back to "hisi". >>> And the DTS is shipped with the driver together. >>> So I think there is no compatible issue here. >>> Please let me know if missed anything. Thanks! >> >> There are three things that can go wrong here, and this is only addressing >> one of them: > > Thanks for the detailed explanation! > >> >> 1. Updating the kernel on a machine with a dtb provided by the firmware >> is a problem if the new driver can not handle the old properties. This >> is correctly handled by the driver's fallback as soon as both trees >> are merged. > > Agreed and the driver has been merged into the v5.11-rc1. Sorry, I made a mistake. It has been merged into linux-next *not* the v5.11-rc1. > >> >> 2. Updating the dtb while running an older kernel is now broken since >> the driver can no longer read the property. This is less critical, but >> it does seem easy enough to work around here by leaving both >> properties in place. > > Yes, it is. > But if leaving both in place, the dtbs_check will report following warning again: > 'hisi,rst-syscon' does not match any of the regexes > > That is why leizhen changed the dtb. > Do you think it is OK to assume no one will use the new dtb with an older kernel? > >> >> 3. Bisecting through the git history across an incompatible change >> means you can run into broken commits. We try hard to avoid that >> if we are aware of a problem in advance. In this case it could be >> avoided by only merging the incompatible DT change in a following >> merge window after the driver change, or (better) by making it >> a backward-compatible change the same way as addressing 2. > > Yes, agreed. > And The DT change pull request is sent after the driver has been merged into v5.11-rc1. I can drop this patch and revert what I have changed in Mauro's following patch: "arm64: dts: hisilicon: hi3670.dtsi: add iomcu_rst" Then resend the pull request. And pick up this patch after the next merge window. Do you think is it OK? Thanks! Best Regards, Wei > > Really appreciate the detail you went to! > > Best Regards, > Wei > >> >> Arnd >> . >> _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel 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=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 510FDC433DB for ; Fri, 29 Jan 2021 01:56:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F162D64DF1 for ; Fri, 29 Jan 2021 01:56:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229866AbhA2B4G (ORCPT ); Thu, 28 Jan 2021 20:56:06 -0500 Received: from szxga06-in.huawei.com ([45.249.212.32]:11471 "EHLO szxga06-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229819AbhA2B4F (ORCPT ); Thu, 28 Jan 2021 20:56:05 -0500 Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4DRgPT6BHQzjDFw; Fri, 29 Jan 2021 09:54:21 +0800 (CST) Received: from [10.40.166.221] (10.40.166.221) by DGGEMS404-HUB.china.huawei.com (10.3.19.204) with Microsoft SMTP Server id 14.3.498.0; Fri, 29 Jan 2021 09:55:11 +0800 Message-ID: <60136AFF.5080204@hisilicon.com> Date: Fri, 29 Jan 2021 09:55:11 +0800 From: Wei Xu User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Arnd Bergmann CC: Zhen Lei , Philipp Zabel , Rob Herring , linux-arm-kernel , devicetree , linux-kernel , Zhangfei Gao , Chen Feng , Manivannan Sadhasivam , "Mauro Carvalho Chehab" Subject: Re: [PATCH v3 2/4] arm64: dts: correct vendor prefix hisi to hisilicon References: <20201208124641.1787-1-thunder.leizhen@huawei.com> <20201208124641.1787-3-thunder.leizhen@huawei.com> <6010B6DE.4060202@hisilicon.com> <60135EBA.5040803@hisilicon.com> In-Reply-To: <60135EBA.5040803@hisilicon.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.40.166.221] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Arnd, On 2021/1/29 9:02, Wei Xu wrote: > Hi Arnd, > > On 2021/1/28 22:08, Arnd Bergmann wrote: >> On Wed, Jan 27, 2021 at 1:42 AM Wei Xu wrote: >>> On 2021/1/27 6:23, Arnd Bergmann wrote: >>>> On Tue, Dec 8, 2020 at 1:46 PM Zhen Lei wrote: >>>>> >>>>> The vendor prefix of "Hisilicon Limited" is "hisilicon", it is clearly >>>>> stated in "vendor-prefixes.yaml". >>>>> >>>>> Fixes: 35ca8168133c ("arm64: dts: Add dts files for Hisilicon Hi3660 SoC") >>>>> Fixes: dd8c7b78c11b ("arm64: dts: Add devicetree for Hisilicon Hi3670 SoC") >>>>> Signed-off-by: Zhen Lei >>>>> Cc: Chen Feng >>>>> Cc: Manivannan Sadhasivam >>>> >>>> I see this change in the pull request I got, but I'm a bit worried about the >>>> incompatible binding change. Wouldn't the correct path forward be to >>>> list both the correct and the incorrect properties, both in the dts file >>>> and in the driver that interprets the properties? >>> >>> Thanks for the comment! >>> The reset driver will look for "hisilicon" firstly and fall back to "hisi". >>> And the DTS is shipped with the driver together. >>> So I think there is no compatible issue here. >>> Please let me know if missed anything. Thanks! >> >> There are three things that can go wrong here, and this is only addressing >> one of them: > > Thanks for the detailed explanation! > >> >> 1. Updating the kernel on a machine with a dtb provided by the firmware >> is a problem if the new driver can not handle the old properties. This >> is correctly handled by the driver's fallback as soon as both trees >> are merged. > > Agreed and the driver has been merged into the v5.11-rc1. Sorry, I made a mistake. It has been merged into linux-next *not* the v5.11-rc1. > >> >> 2. Updating the dtb while running an older kernel is now broken since >> the driver can no longer read the property. This is less critical, but >> it does seem easy enough to work around here by leaving both >> properties in place. > > Yes, it is. > But if leaving both in place, the dtbs_check will report following warning again: > 'hisi,rst-syscon' does not match any of the regexes > > That is why leizhen changed the dtb. > Do you think it is OK to assume no one will use the new dtb with an older kernel? > >> >> 3. Bisecting through the git history across an incompatible change >> means you can run into broken commits. We try hard to avoid that >> if we are aware of a problem in advance. In this case it could be >> avoided by only merging the incompatible DT change in a following >> merge window after the driver change, or (better) by making it >> a backward-compatible change the same way as addressing 2. > > Yes, agreed. > And The DT change pull request is sent after the driver has been merged into v5.11-rc1. I can drop this patch and revert what I have changed in Mauro's following patch: "arm64: dts: hisilicon: hi3670.dtsi: add iomcu_rst" Then resend the pull request. And pick up this patch after the next merge window. Do you think is it OK? Thanks! Best Regards, Wei > > Really appreciate the detail you went to! > > Best Regards, > Wei > >> >> Arnd >> . >>