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 C0090EB64DA for ; Wed, 5 Jul 2023 15:49:55 +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:In-Reply-To:MIME-Version: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:References: List-Owner; bh=uLyq0GUKEIL7+Gfo2TAMsdtqPRZYCXCE8S52bvr1tac=; b=H92YesSiGNsM6s gFEIAwLkK025QPx1l33CeKVmC3v3bm/8BnzrcVHi7Bv99tSjr64sJEuosInEd6VXL+MQnVXnzqC53 0Pd8B1Fu/jl4LEnLx3L24j2DnuESkTwH91acvsIJGa17H6usw3hnH+kHOhUNmZo/7TpVG7THuTR++ FM06/03/fJ4Im9zd3JJc4MiUahwZ4V+Vay0V3WIEldF5f2yEHoEO5aGzEfb3pLjDoebZDqNSx+FkO GCDyPLSCBLTf3GmfIegGHFE0NSu7tyXAePO+pgIXkQuf4gqsZBuxB7uRdz0ONM47nlXYwWjuqp9gO sHXHynSY9f1aCJoeuihQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qH4l3-00GNo0-30; Wed, 05 Jul 2023 15:49:33 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qH4l1-00GNnG-04 for linux-arm-kernel@lists.infradead.org; Wed, 05 Jul 2023 15:49:32 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3704061601; Wed, 5 Jul 2023 15:49:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A42CC433CA; Wed, 5 Jul 2023 15:49:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1688572169; bh=Wk/EDtW10p6pp6WTwmzgYg6QrckaCsMdnVGkAU0iNaM=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=E84fDqN41ael8RB8O2f19tkcvhuFrd6zuDsO1tXY+Z69XQqtcA8ljbDN3XG9xIvif b7leT2sE2Va1DD2f17avNwUaKmLa34lG+4mlM4x85RPbEOknw69N/pYzYezhSFqqup 0KKeAOQsCvZy5uN4LSh+o5Cuu/ii46NBVP7cgrdoJfcSF79vYVfpa9zPF4oSC8QeIC XEIYuhbcxhv3IHSSnzV4/Pyj4lk+mtohnz6+vdgt9RJYCgiy69Qbpig58lUkHLagBQ 3mTvoW1lDdZm3CXh2XjueeU6y+5BW3v9XYvGubIqP3WSEdI1gyDCiM2XQ4xtlhDH0t XX/gNQXDhk1xQ== Date: Wed, 5 Jul 2023 10:49:27 -0500 From: Bjorn Helgaas To: "Verma, Achal" Cc: Vignesh Raghavendra , Tom Joseph , Lorenzo Pieralisi , Krzysztof Wilczy_ski , Rob Herring , Bjorn Helgaas , linux-omap@vger.kernel.org, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [EXTERNAL] Re: [PATCH] PCI: j721e: Fix delay before PERST# deassert Message-ID: <20230705154927.GA62511@bhelgaas> 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-20230705_084931_119443_84E10A08 X-CRM114-Status: GOOD ( 25.29 ) 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 On Tue, Jul 04, 2023 at 09:36:43PM +0530, Verma, Achal wrote: > On 7/3/2023 9:51 PM, Bjorn Helgaas wrote: > > In subject, "Fix" doesn't convey much information. Does it increase? > > Decrease? How much time are we talking about? PERST# deassert is at > > one end of the delay; what event is at the other end? > > How about "Increase delay to 100ms for PERST# deassert from moment > power-rails achieve operating limits" Maybe something like "Delay 100ms T_PVPERL from power stable to PERST# inactive" to match the language in the spec? > > Is this delay for the benefit of the Root Port or for the attached > > Endpoint? If the latter, my guess is that some Endpoints might > > tolerate the current shorter delay, while others might require > > more, and it doesn't sound like "TI's K3 SoC" would be relevant > > here. > > Its for the endpoints, TI's EVB doesn't exhibit any issues with > 100us delay but some customer reported the issue with shorter delay. I wouldn't bother mentioning "some custom platform implemented using TI's K3 SOCs" then, because the problem is that the driver didn't observe T_PVPERL, so the problem will happen with some endpoints but not others. > > Numbers like 100ms that come from the PCIe specs should have #defines > > for them. If we don't have one already, can you add one, please? > > Sure, will do it in next revision but should this go in some generic PCI > header file or just pci-j721e.c I think it should be in drivers/pci/pci.h so all the controller drivers can use the same thing. Obviously none of them *currently* use it, although there are a bunch of "msleep(100)" and a few comments that mention T_PVPERL. Bjorn _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel