From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Reed Subject: Re: [PATCH]: Re: qla1280.c broken on SGI visws, PCI coherency problem Date: Tue, 13 Dec 2005 12:15:50 -0600 Message-ID: <439F0FD6.30701@sgi.com> References: <4399D6EB.4080603@c-lab.de> <439A17BE.5000904@sgi.com> <439DE50B.90007@sgi.com> <1134424057.3713.18.camel@mulgrave> <439E0112.1030801@sgi.com> <439ECB2E.7070103@sgi.com> <1134485413.3356.2.camel@mulgrave> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from omx2-ext.sgi.com ([192.48.171.19]:21479 "EHLO omx2.sgi.com") by vger.kernel.org with ESMTP id S932526AbVLMSQH (ORCPT ); Tue, 13 Dec 2005 13:16:07 -0500 In-Reply-To: <1134485413.3356.2.camel@mulgrave> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: pazke@donpac.ru, Michael Joosten , linux-scsi@vger.kernel.org James Bottomley wrote: > On Tue, 2005-12-13 at 07:22 -0600, Michael Reed wrote: >> I believe the biggest issue with VISWS is that it appears to need >> mmiowb() and we likely don't know how to implement it. Hence, for >> that platform, it would make sense to replace the mmiowb() with a >> posting read. > > Well, there's an easy way to tell ... the reason for the mmiowb in the > qla1280 driver is supposed to be an SMP race, according to the > description, so if it fails on UP as well there's something else going > on here ... > > I'm still suspicious because the mmiowb() in this driver replaced a > posted write flush instruction, which altered the behaviour of the > driver. The qla1280 is just rare enough that it might have taken this > long to notice ... Yup. But.... keep in mind that the failing platform is the SGI VISWS, the child of a PC and an O2. I'd be much more suspicious if it failed on a generic PC. (It also works fine on SGI Altix, a platform which has implemented mmiowb().) Perhaps Mr. Joosten can confirm his failing case with the UP kernel? Mike > > James > >