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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 9A99DEB64DC for ; Mon, 3 Jul 2023 13:50:18 +0000 (UTC) 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:MIME-Version:Subject:References: In-Reply-To:Message-ID: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=Ojkwou2afDllX0VQls1B9FEU12HEXMGkW9IFWBPqsJM=; b=Eydz8Xo0Sa8zMfGZqd+OdNFhly epa7HxbEq3yM+TvB7Q7zrt6v7MtQFX6jDBhb71DutDQk1m/dQej9wpYPpsUMBJ3enO+xVUjSfXoRC vUpSs7UGF1RHUdODVz2i7SB15oFYX+r/Tbhxccj9MeNYwxmy64msVRvX9I93mdAkCHIYqSzzM8CP1 0/E35IEfUjop/3WgZMYVECLZ46MVs0kTgBKZZHQpTPAjCC4OOXW6MGiBBUoAeTabHntRFSBeytw2M WnVOX2E5JjjqM9W//mlzoFT9lI+muAgnh504qb4/wzWwgYgdeQQ8UtBInAf+rG0HLKTSJb8+U1KJr POC0iafA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qGJw3-00Ag2r-32; Mon, 03 Jul 2023 13:49:47 +0000 Received: from sender4-op-o15.zoho.com ([136.143.188.15]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qGJw1-00Ag1I-0B for linux-arm-kernel@lists.infradead.org; Mon, 03 Jul 2023 13:49:46 +0000 ARC-Seal: i=1; a=rsa-sha256; t=1688392179; cv=none; d=zohomail.com; s=zohoarc; b=SP9ImYKJXEf65WKqag/ju5y526ZfAFIBV4itRdPacBQ3+yv5KnCru8ASuO9Hlo1Gt2oK5OjGfBVUSMXqhHesfFw44l8G58ol9rDbTZs4DUmr2mNbiu8R7n5wTKI8SpMtNvhTnFheLb4J/UW25OjOE1YUX+l1vx5BFFQaQfHSCDs= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1688392179; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:To; bh=0juxJGr0V0mWBkxuSy/zAkO1ju2c9SqaUoNVC94Ta+g=; b=DX6QQuBCyOLO33f2JL3SPON+PDyKnDqY1eJlK7uslPKmFb4TRsfiJgmyoGAQztmM7A8PKEZK+FLdZdB8gsIsKBIY7lsV6kcJNwhVBuvbkVjUmHLbEUBwrCT7wWyc8/wZWC1zStk5lUGlH6HoxgGCe+XO8Lghe/GrXoaadX9RSFw= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=linux.beauty; spf=pass smtp.mailfrom=me@linux.beauty; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1688392178; s=zmail; d=linux.beauty; i=me@linux.beauty; h=Date:Date:From:From:To:To:Cc:Cc:Message-ID:In-Reply-To:References:Subject:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Reply-To; bh=0juxJGr0V0mWBkxuSy/zAkO1ju2c9SqaUoNVC94Ta+g=; b=HWnuovJb6yqvdgTAK2CNyPNMuAPlm0fFmH8WjjDVWS0zulM3dFFROXLQSFR/CqSV SmRDdJwch6aB7hRBeuhgl35fz65Jn4i+LDo+6X6IBx8lnPlgfa1Pq9/V20UT1owcSFJ WugwavBR6h6CxjQqQP3VeKrrITPPXzcFwAyMXimw= Received: from mail.zoho.com by mx.zohomail.com with SMTP id 1688392177737939.3774690465508; Mon, 3 Jul 2023 06:49:37 -0700 (PDT) Date: Mon, 03 Jul 2023 21:49:37 +0800 From: Li Chen To: "Achal Verma" Cc: "Vignesh Raghavendra" , "Tom Joseph" , "Lorenzo Pieralisi" , "Krzysztof Wilczy_ski" , "Rob Herring" , "Bjorn Helgaas" , "linux-omap" , "linux-pci" , "linux-arm-kernel" , "linux-kernel" Message-ID: <1891c041807.fea67a55448140.3454059194195387266@linux.beauty> In-Reply-To: <20230703112914.68806-1-a-verma1@ti.com> References: <20230703112914.68806-1-a-verma1@ti.com> Subject: Re: [PATCH] PCI: j721e: Fix delay before PERST# deassert MIME-Version: 1.0 Importance: Medium User-Agent: Zoho Mail X-Mailer: Zoho Mail X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230703_064945_163039_C2CC3906 X-CRM114-Status: UNSURE ( 9.66 ) X-CRM114-Notice: Please train this message. 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="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 Achal, ---- On Mon, 03 Jul 2023 19:29:14 +0800 Achal Verma wrote --- > As per the PCIe Card Electromechanical specification REV. 3.0, PERST# > signal should be de-asserted after minimum 100ms from the time power-rails > become stable. Current delay of 100us is observed to be not enough on some > custom platform implemented using TI's K3 SOCs. > > So, to ensure 100ms delay to give sufficient time for power-rails and > refclk to become stable, change delay from 100us to 100ms. What problems could arise if the delay is too small? Would some endpoints not be able to detect it? Regards, Li _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel