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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C33CDC433EF for ; Thu, 14 Apr 2022 07:49:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231375AbiDNHv6 (ORCPT ); Thu, 14 Apr 2022 03:51:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50754 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231676AbiDNHv5 (ORCPT ); Thu, 14 Apr 2022 03:51:57 -0400 X-Greylist: delayed 2305 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Thu, 14 Apr 2022 00:49:31 PDT Received: from imap3.hz.codethink.co.uk (imap3.hz.codethink.co.uk [176.9.8.87]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D0CA12602; Thu, 14 Apr 2022 00:49:29 -0700 (PDT) Received: from cpc152649-stkp13-2-0-cust121.10-2.cable.virginm.net ([86.15.83.122] helo=[192.168.0.21]) by imap3.hz.codethink.co.uk with esmtpsa (Exim 4.92 #3 (Debian)) id 1netd6-0005jh-I9; Thu, 14 Apr 2022 08:11:00 +0100 Message-ID: <3acd20b2-5882-7cc0-8a7b-7b406b768c1c@codethink.co.uk> Date: Thu, 14 Apr 2022 08:11:00 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [V3] PCI: fu740: Drop to 2.5GT/s to fix initial device probing on some boards Content-Language: en-GB To: "Maciej W. Rozycki" Cc: Alexandre Ghiti , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Bjorn Helgaas , Palmer Dabbelt , Rob Herring , Lorenzo Pieralisi , Greentime Hu , Paul Walmsley , David Abdurachmanov , Neill Whillans References: <20220318152430.526320-1-ben.dooks@codethink.co.uk> <2442936e-a53e-59bf-488f-95eac26d1252@ghiti.fr> <85e864fd-762e-0780-f829-bfbb178ab24e@ghiti.fr> From: Ben Dooks Organization: Codethink Limited. In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On 14/04/2022 01:10, Maciej W. Rozycki wrote: > On Wed, 23 Mar 2022, Ben Dooks wrote: > >>> FWIW, I have tested this and it solved my issue with nvme not being probed, >>> so: >>> >>> Tested-by: Alexandre Ghiti >> >> Ok, great. Our test rig seems to be still working with this. > > I ran simple verification of your change by interrupting U-Boot after a > power-up and issuing: > > => setenv boot_pci_enum true > > at the command prompt before booting from the uSD card and curiously > enough the root port comes up with the Link Capabilities Register > reporting the lack of Link Bandwidth Notification Capability in this > scenario, while it reports its presence if booted undisturbed, i.e.: > > LnkCap: Port #0, Speed 8GT/s, Width x8, ASPM L0s L1, Exit Latency L0s <4us, L1 <4us > ClockPM- Surprise- LLActRep+ BwNot- ASPMOptComp+ > > vs: > > LnkCap: Port #0, Speed 8GT/s, Width x8, ASPM L0s L1, Exit Latency L0s <4us, L1 <4us > ClockPM- Surprise- LLActRep+ BwNot+ ASPMOptComp+ > > It is fully reproducible. > > Any idea what might be causing it? I can't see it being explicitly set > or cleared anywhere, be it in U-Boot or Linux, so it must be done by the > device itself depending on something. And the lack of this capability > seems to me like non-compliance for a multiple-lane, multiple-speed > device. I'll see if we can reproduce this -- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius https://www.codethink.co.uk/privacy.html