Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753054AbdF2SiF (ORCPT ); Thu, 29 Jun 2017 14:38:05 -0400 Received: from ale.deltatee.com ([207.54.116.67]:51761 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751941AbdF2Sh7 (ORCPT ); Thu, 29 Jun 2017 14:37:59 -0400 To: Allen Hubbe , linux-ntb@googlegroups.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org References: <20170629032648.3073-1-logang@deltatee.com> <20170629032648.3073-13-logang@deltatee.com> <000201d2f103$2f3d2d20$8db78760$@dell.com> Cc: "'Jon Mason'" , "'Dave Jiang'" , "'Bjorn Helgaas'" , "'Greg Kroah-Hartman'" , "'Kurt Schwemmer'" , "'Stephen Bates'" , "'Serge Semin'" From: Logan Gunthorpe Message-ID: <9a280b29-4e1b-cf4a-54c2-25a522834879@deltatee.com> Date: Thu, 29 Jun 2017 12:37:46 -0600 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <000201d2f103$2f3d2d20$8db78760$@dell.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.111 X-SA-Exim-Rcpt-To: fancer.lancer@gmail.com, sbates@raithlin.com, kurt.schwemmer@microsemi.com, gregkh@linuxfoundation.org, bhelgaas@google.com, dave.jiang@intel.com, jdmason@kudzu.us, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-ntb@googlegroups.com, Allen.Hubbe@dell.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH 12/16] switchtec_ntb: add link management X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 673 Lines: 13 On 6/29/2017 12:11 PM, Allen Hubbe wrote: > Should we only set self_partition? I think each peer should be able to set preferred speed, and negotiate down. As written here, the last peer to set the speed overrides the setting on the peer, and even that is not atomic if they race. This function isn't actually setting the link speed. (Though I can understand the confusion from the name.) It's just reporting the slowest speed on the link between the peers for the link_is_up function. (Each port will have negotiated it's own speed). I don't think switchtec has the ability to actually change the port speed or width. (Seeing they are negotiated on boot). Logan