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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BC405C433EF for ; Wed, 24 Nov 2021 09:16:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230089AbhKXJTw (ORCPT ); Wed, 24 Nov 2021 04:19:52 -0500 Received: from hostingweb31-40.netsons.net ([89.40.174.40]:59633 "EHLO hostingweb31-40.netsons.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241440AbhKXJT0 (ORCPT ); Wed, 24 Nov 2021 04:19:26 -0500 Received: from [79.2.93.196] (port=52016 helo=[192.168.101.73]) by hostingweb31.netsons.net with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94.2) (envelope-from ) id 1mpoNw-0004yt-EW; Wed, 24 Nov 2021 10:16:12 +0100 Subject: Re: [PATCH v3 3/3] PCI: apple: Fix #PERST polarity To: Marc Zyngier Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, =?UTF-8?Q?Pali_Roh=c3=a1r?= , Alyssa Rosenzweig , Lorenzo Pieralisi , Bjorn Helgaas , Mark Kettenis , kernel-team@android.com References: <20211123180636.80558-1-maz@kernel.org> <20211123180636.80558-4-maz@kernel.org> <453389da-b041-94b3-009e-6c6323134936@lucaceresoli.net> <87fsrmc4e6.wl-maz@kernel.org> From: Luca Ceresoli Message-ID: Date: Wed, 24 Nov 2021 10:16:10 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: <87fsrmc4e6.wl-maz@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - hostingweb31.netsons.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - lucaceresoli.net X-Get-Message-Sender-Via: hostingweb31.netsons.net: authenticated_id: luca+lucaceresoli.net/only user confirmed/virtual account not confirmed X-Authenticated-Sender: hostingweb31.netsons.net: luca@lucaceresoli.net X-Source: X-Source-Args: X-Source-Dir: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 24/11/21 10:02, Marc Zyngier wrote: > On Tue, 23 Nov 2021 21:36:11 +0000, > Luca Ceresoli wrote: >> >> Hi Mark, >> >> On 23/11/21 19:06, Marc Zyngier wrote: >>> Now that #PERST is properly defined as active-low in the device tree, >>> fix the driver to correctly drive the line indemendently of the >>> implied polarity. >>> >>> Fixes: 1e33888fbe44 ("PCI: apple: Add initial hardware bring-up") >>> Suggested-by: Pali Rohár >>> Signed-off-by: Marc Zyngier >> >> Thanks for quickly addressing this! >> >> Do we need a transition path for backward compatibility with old DTs >> already around? Something like this [0]. You said [1] the DT actually >> used is not even the one in the kernel, thus how do we guarantee DT and >> driver switch to the new polarity all at once? > > No. As it turns out, neither u-boot nor OpenBSD (the only two other > payloads that can boot on M1) are upstreamed yet. So we're still in > that stage where we don't need to maintain backward compatibility. If > we don't get this patches merged by the end of this cycle, we will > have to revisit this though. Good news! Reviewed-by: Luca Ceresoli -- Luca