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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 05CD3C433EF for ; Thu, 18 Nov 2021 10:45:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DB9EA613D0 for ; Thu, 18 Nov 2021 10:45:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245740AbhKRKsJ (ORCPT ); Thu, 18 Nov 2021 05:48:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:37414 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235730AbhKRKsG (ORCPT ); Thu, 18 Nov 2021 05:48:06 -0500 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1D83C61AA3; Thu, 18 Nov 2021 10:45:07 +0000 (UTC) Received: from sofa.misterjones.org ([185.219.108.64] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1mneue-006I7g-UW; Thu, 18 Nov 2021 10:45:05 +0000 Date: Thu, 18 Nov 2021 10:45:04 +0000 Message-ID: <87lf1l7nf3.wl-maz@kernel.org> From: Marc Zyngier To: Pali =?UTF-8?B?Um9ow6Fy?= Cc: Bjorn Helgaas , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, kernel-team@android.com, Alyssa Rosenzweig , Lorenzo Pieralisi , Bjorn Helgaas Subject: Re: [PATCH] PCI: apple: Reset the port for 100ms on probe In-Reply-To: <87o86h7pex.wl-maz@kernel.org> References: <20211117160053.232158-1-maz@kernel.org> <20211117201245.GA1768803@bhelgaas> <20211117202859.2m5sqwz6xsjgldji@pali> <87o86h7pex.wl-maz@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: pali@kernel.org, helgaas@kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, kernel-team@android.com, alyssa@rosenzweig.io, lorenzo.pieralisi@arm.com, bhelgaas@google.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 18 Nov 2021 10:01:58 +0000, Marc Zyngier wrote: > > There is also a third delay (Tperst-clk) which represents the time > required for the clock to ramp up before releasing #PERST. No, there > is no value associated with this. Actually, there is. At least the PCIe CMS r2.0 (2.6.2. AC Specifications) does provide a table of the timings. Tperst-clk has a minimum value of 100us. Which means I can tighten things further. M. -- Without deviation from the norm, progress is not possible.