From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luben Tuikov Subject: Re: [PATCH 1/4] sas: add flag for locally attached PHYs Date: Thu, 20 Oct 2005 12:08:24 -0400 Message-ID: <4357C0F8.3030400@adaptec.com> References: <91888D455306F94EBD4D168954A9457C048F08AE@nacos172.co.lsil.com> <4356B3D3.1010203@adaptec.com> <20051020141123.GA7119@lst.de> <4357B7C5.9000709@adaptec.com> <20051020154942.GA12809@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from magic.adaptec.com ([216.52.22.17]:33183 "EHLO magic.adaptec.com") by vger.kernel.org with ESMTP id S932334AbVJTQI3 (ORCPT ); Thu, 20 Oct 2005 12:08:29 -0400 In-Reply-To: <20051020154942.GA12809@lst.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Christoph Hellwig Cc: "Moore, Eric Dean" , jejb@steeleye.com, linux-scsi@vger.kernel.org On 10/20/05 11:49, Christoph Hellwig wrote: > Hi Christoph, For some reason I thought that I was quoting specs and showing constructive ideas (i.e. things you can sit down and start coding). I'm sorry that you feel that it is "useless rants". On a topic note: It appears that the "sas transport attributes" are nothing more than SDI/CSMI. > Yes, we have two cases, local phy and phy on an expander. The proper > way to support remote phys is via smp passthru as we hopefully agree. > Right now the sas transport class doesn't do smp passthru (although > I'm working on it) so we only implement local link stats. You are so much better off implementing SDI/CSMI as per the spec. Normally, at companies, projects have a "specificaion" and "required functionality". What is the "specificaion" and "required functionality" at hand? Note that there are LSI/HP customers who are completely _happy_ to use CSMI as provided by LSI and they are not interested in what-have-you-not. The easiest way to make those customers happy and keep them happy is to provide general SDI/CSMI facitliy and _you have a spec on that_. > Once we have > smp passthru we can support link stats, in one of two ways: > > - do it in userland as in your example program. in that case we don't > need to do anything in kernel land and need the local_attached flag > to disable this functionality for expander phys. > - do it in kernel, in which case the transport class must call the smp > passthru entry point of the driver to query link stats, so it needs > the local_attached flag aswell for that. > > What's your problem with the flag now? It is ugly, it is a (brown) paper bag solution, it is a work around. Take a look at the phy attributes as per the SAS spec. Then take a look at struct sas_phy in include/scsi/sas/sas_class.h. Do you see such a flag in either reference? Luben -- http://linux.adaptec.com/sas/ http://www.adaptec.com/sas/