From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: does sym53c8xx_2 hardware support hotplug Date: Thu, 24 Apr 2008 11:25:41 +0200 Message-ID: <48105215.8040109@suse.de> References: <480F979E.5060302@cs.wisc.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from cantor.suse.de ([195.135.220.2]:52057 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751056AbYDXJZn (ORCPT ); Thu, 24 Apr 2008 05:25:43 -0400 In-Reply-To: <480F979E.5060302@cs.wisc.edu> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Mike Christie Cc: SCSI Mailing List , matthew@wil.cx Hi Mike, Mike Christie wrote: > Hi, >=20 > Does the hardware sym53c8xx_2 works with support removing and adding=20 > devices? >=20 Oh. Hmm. That is tricky and complicated. > When using sym53c8xx_2 if we find storage, remove the device using th= e=20 > sysfs/proc interface, then physically remove the device, everything g= oes=20 > well. However, if we physically plug the disk back in and try to read= d=20 > it through the sysfs/proc scanning interfaces, it looks like=20 > scsi_scan.c's inquiry will time out. This causes the sym error handle= r=20 > to run, which works great and we end up doing a BUS RESET (BDR failed= so=20 > we got escalated), and after that the inqiury is retried and we find = the=20 > device and it works fine. >=20 Yes. > Is the inquiry timing out expected? Does the hardware even support=20 > hotplug? Or does it support it partially support it (support it with=20 > some help), and we are we supposed to be manually resetting the bus,=20 > with something like a sg_reset, after we have physically plug the dis= k=20 > back in? >=20 Hi, join the club. As the saying goes: Radio Yerewan answers: in principle, yes. The whole matter of SCSI parallel hotplugging depends strongly on the backplane. For fun reading have a look at=20 SPI-3 Annex D: Removal and insertion of SCSI devices. It basically leaves it open to the vendor of the backplane how much intelligence he wants to put in there. But yes, sending a SCSI reset is listed there. It actually states that the RST line should be asserted continuously by the initiator during the hotplugging process. HTH. Cheers, Hannes --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: Markus Rex, HRB 16746 (AG N=FCrnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html