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=-5.5 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,USER_AGENT_SANE_1 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 838D1C2B9F4 for ; Tue, 22 Jun 2021 11:58:12 +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 4ED3D60FE9 for ; Tue, 22 Jun 2021 11:58:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4ED3D60FE9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.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=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc: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=cwnY/Q+9GYfn8lo5h4i8zFZSGyvA8J1uwXb0pUSpDKE=; b=vkwa49T1mP9j6q fqceOh3JwMWRZhC34qs4GpWPhPE/FSn2y4pP9rb2AJt031sGDz5Eb4tNeClDlmc8kGZUv/uZx7BIb 7Lc7chjwutkJ/aQ3IteZvrAZS7E+aYwuiG52pkPYkY+FFTTGF9mZco+eY0723hTONnieBuN/fkYsu 3AZtApZ3+7K6Its/t39amaFpxI04LhObsPt6UO7SGCjXvT9R45F036X/3dUT0RxnJvALZjMCPaPnl xGS+A8wfRkXw4NkDCsFy/DFev1gCv2evhRdik8NdLAzLf3Mx3wsd/XKp2EmtVik5Eu9BtbF9IgjPf HUPsDFkcswENKFyevYeQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lvf0q-0072WJ-8q; Tue, 22 Jun 2021 11:56:16 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lvf0m-0072VN-Of for linux-arm-kernel@lists.infradead.org; Tue, 22 Jun 2021 11:56:14 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6CCFF11D4; Tue, 22 Jun 2021 04:56:10 -0700 (PDT) Received: from lpieralisi (e121166-lin.cambridge.arm.com [10.1.196.255]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 186C93F694; Tue, 22 Jun 2021 04:56:08 -0700 (PDT) Date: Tue, 22 Jun 2021 12:56:04 +0100 From: Lorenzo Pieralisi To: Pali =?iso-8859-1?Q?Roh=E1r?= , linus.walleij@linaro.org, kishon@ti.com Cc: Luca Ceresoli , linux-pci@vger.kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Rob Herring , Bjorn Helgaas Subject: Re: [PATCH v2] PCI: dra7xx: Fix reset behaviour Message-ID: <20210622115604.GA25503@lpieralisi> References: <20210531090540.2663171-1-luca@lucaceresoli.net> <20210531133211.llyiq3jcfy25tmz4@pali> <8ff1c54f-bb29-1e40-8342-905e34361e1c@lucaceresoli.net> <9fdbada4-4902-cec1-f283-0d12e1d4ac64@ti.com> <20210531162242.jm73yzntzmilsvbg@pali> <8207a53c-4de9-d0e5-295a-c165e7237e36@lucaceresoli.net> <20210622110627.aqzxxtf2j3uxfeyl@pali> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210622110627.aqzxxtf2j3uxfeyl@pali> User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210622_045612_914046_8C091055 X-CRM114-Status: GOOD ( 21.68 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org [Adding Linus for GPIO discussion, thread: https://lore.kernel.org/linux-pci/20210531090540.2663171-1-luca@lucaceresol= i.net] On Tue, Jun 22, 2021 at 01:06:27PM +0200, Pali Roh=E1r wrote: > Hello! > = > On Tuesday 22 June 2021 12:57:22 Luca Ceresoli wrote: > > Nothing happened after a few weeks... I understand that knowing the > > correct reset timings is relevant, but unfortunately I cannot help much > > in finding out the correct values. > > = > > However I'm wondering what should happen to this patch. It *does* fix a > > real bug, but potentially with an incorrect or non-optimal usleep range. > > Do we really want to ignore a bugfix because we are not sure about how > > long this delay should be? > = > As there is no better solution right now, I'm fine with your patch. But > patch needs to be approved by Lorenzo, so please wait for his final > answer. I am not a GPIO expert and I have a feeling this is platform specific beyond what the PCI specification can actually define architecturally. There are two things I'd like to see: 1) If Linus can have a look at the GPIO bits in this thread that would definitely help clarify any pending controversy 2) Kishon to test on *existing* platforms and confirm there are no regressions triggered > I would suggest to add a comment for call "usleep_range(1000, 2000);" > that you have chosen some "random" values which worked fine on your > setup and that they fix mentioned bug. Comment just to mark this sleep > code that is suboptimal / not-so-correct and to prevent other people to > copy+paste this code into other (new) drivers... Yes a comment would help but as I say above I am afraid this is a platform specific set-up, ie that delay is somewhat tied to a platform, not sure there is anything we can do. If Linus and Kishon are happy with the approach we can merge this patch. Lorenzo _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel