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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 97FE3C54E49 for ; Thu, 7 May 2020 21:10:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D2DD20870 for ; Thu, 7 May 2020 21:10:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588885821; bh=EFmtHjFZLnql7id7dydgW0zEPtomPgKv+eg6JMFJ1Oc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=qrZ0zNNE+7H0Njyi2ocRtZ64tvaDMB9macs1qm8VABsqkjqKHmwiH9eYm5L7odsCd qHQsqkLpgcl0iBGkmZbFg/Ae1b7YTRAiBeInQYSUU47JfTa/XmZjSw7PIXT+dvJ8dy QGjsMiZn06m+QwHoZH8Bt6ilOkD3+pM0E308U8rQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726616AbgEGVKU (ORCPT ); Thu, 7 May 2020 17:10:20 -0400 Received: from mail-oi1-f195.google.com ([209.85.167.195]:38001 "EHLO mail-oi1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726218AbgEGVKU (ORCPT ); Thu, 7 May 2020 17:10:20 -0400 Received: by mail-oi1-f195.google.com with SMTP id r66so6525706oie.5; Thu, 07 May 2020 14:10:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=vOJAT5al1D5jfLK3KCZe+EiKaiKoKpmEc2pvPJsPSMI=; b=Z2hHdYFTCOCunFIh8PZ1MiclTsSpNzzJeSfr2gnLT/Nwumc+K0vDpSJYVVhTbG44tL x0weV1osoeDSUDY/Szfmyj5cFBUuP5P6N+aoFlz9YxgA1LSdnbxm+SGnLfCrQh2A8tsf PVrbMHUXWfWtj8QypCcvVH/Cq2rzhBkG6kUolLuJLo7jf0U/xjsOcgrBHTlQRzf65pQK RFLtCsf+WvHy9oTX1BzVgUu1KAMpbcApbppSFTaANNwgzjCvkba++DRbtRBsO0SzTaZ0 awaOzkvqU+BpHGQMvelEGgHNatPielw7hLZ6XKUhqva2HwDkVrNxLlEkOGmDUu4B24y5 NSTA== X-Gm-Message-State: AGi0PuaKrUh+K1bFcEP5xhGoMM2Azvo84C3BuzESmQf0S8TEIbmkDc6k MOwOXSiTYawkAs9wXEuxSDKfUrU= X-Google-Smtp-Source: APiQypKC8n4GIaDfFsylvmEQK/cN0izFWrgqXOZf1olkbDe/mTybNEvl2zkbWwcKLeEyl0uWqLvP3Q== X-Received: by 2002:aca:f454:: with SMTP id s81mr7657610oih.138.1588885817620; Thu, 07 May 2020 14:10:17 -0700 (PDT) Received: from rob-hp-laptop (24-155-109-49.dyn.grandenetworks.net. [24.155.109.49]) by smtp.gmail.com with ESMTPSA id p13sm1735241oom.34.2020.05.07.14.10.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 May 2020 14:10:17 -0700 (PDT) Received: (nullmailer pid 32069 invoked by uid 1000); Thu, 07 May 2020 21:10:15 -0000 Date: Thu, 7 May 2020 16:10:15 -0500 From: Rob Herring To: Pali =?iso-8859-1?Q?Roh=E1r?= Cc: Jason Cooper , Andrew Lunn , Gregory Clement , Sebastian Hesselbarth , Thomas Petazzoni , Lorenzo Pieralisi , Andrew Murray , Bjorn Helgaas , Remi Pommarel , Marek =?iso-8859-1?Q?Beh=FAn?= , Tomasz Maciej Nowak , Xogium , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Subject: Re: [PATCH v4 04/12] PCI: aardvark: Improve link training Message-ID: <20200507211015.GA31477@bogus> References: <20200430080625.26070-1-pali@kernel.org> <20200430080625.26070-5-pali@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200430080625.26070-5-pali@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 30 Apr 2020 10:06:17 +0200, =?UTF-8?q?Pali=20Roh=C3=A1r?= wrote: > From: Marek Behún > > Currently the aardvark driver trains link in PCIe gen2 mode. This may > cause some buggy gen1 cards (such as Compex WLE900VX) to be unstable or > even not detected. Moreover when ASPM code tries to retrain link second > time, these cards may stop responding and link goes down. If gen1 is > used this does not happen. > > Unconditionally forcing gen1 is not a good solution since it may have > performance impact on gen2 cards. > > To overcome this, read 'max-link-speed' property (as defined in PCI > device tree bindings) and use this as max gen mode. Then iteratively try > link training at this mode or lower until successful. After successful > link training choose final controller gen based on Negotiated Link Speed > from Link Status register, which should match card speed. > > Signed-off-by: Pali Rohár > Signed-off-by: Marek Behún > --- > drivers/pci/controller/pci-aardvark.c | 114 ++++++++++++++++++++------ > 1 file changed, 89 insertions(+), 25 deletions(-) > Reviewed-by: Rob Herring