From mboxrd@z Thu Jan 1 00:00:00 1970 From: Douglas Gilbert Subject: Re: [PATCH] scsi_transport_spi: Export host width and HBA id Date: Wed, 01 Jun 2011 11:15:43 -0400 Message-ID: <4DE6579F.8080402@interlog.com> References: <201106011318.p51DImMr003035@pentland.suse.de> <1306940171.11897.52.camel@mulgrave.site> <4DE65408.2020502@suse.de> Reply-To: dgilbert@interlog.com Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.infotech.no ([82.134.31.41]:37562 "EHLO smtp.infotech.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757990Ab1FAPQF (ORCPT ); Wed, 1 Jun 2011 11:16:05 -0400 In-Reply-To: <4DE65408.2020502@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Hannes Reinecke Cc: James Bottomley , James Bottomley , linux-scsi@vger.kernel.org On 11-06-01 11:00 AM, Hannes Reinecke wrote: > On 06/01/2011 04:56 PM, James Bottomley wrote: >> On Wed, 2011-06-01 at 15:18 +0200, Hannes Reinecke wrote: >>> Currently it's impossible to find out if the host supports >>> wide SCSI unless you're committed to trawl through syslog. >>> And it's near impossible to find the actual HBA id, which >>> is settable for some SCSI HBAs (like aic7xxx). >>> So export them via sysfs. >> >> Um, that's what the the >> >> /sys/class/spi_transport/target/max_width >> >> parameter gives you, isn't it? >> >> max_width tells you if the HBA/device combination supports wide; width >> tells you if the device is using it. >> > Not quite. You'll only have that parameter if there is a target attached to the > HBA. > If there is none you still wouldn't know how far you should be scanning as there > won't be any indicator in sysfs. > > In this case that's an ESX server emulating an sym53c8xx HBA. > And disks attached to it on the fly. > If you start up with no disks attached and attach a new disc > to eg target ID 12 you're stuck. It is about time that VMware emulated SAS rather than SPI for virtual storage. Then if something changes, ESX can emulate a SAS Broadcast(Change) and then smarter SAS HBA drivers will run their discover process and find the changes. Doug Gilbert