From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: RE: Sample implementation of a scheme to handle missing interrupts Date: Mon, 28 Jul 2008 15:45:01 -0500 Message-ID: <1217277901.3503.143.camel@localhost.localdomain> References: <660360F4F2570145BD872F298951B17A3AC7E178@cosmail03.lsi.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from accolon.hansenpartnership.com ([76.243.235.52]:33560 "EHLO accolon.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760396AbYG1Upb (ORCPT ); Mon, 28 Jul 2008 16:45:31 -0400 In-Reply-To: <660360F4F2570145BD872F298951B17A3AC7E178@cosmail03.lsi.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: "Moore, Eric" Cc: Matthew Wilcox , "linux-scsi@vger.kernel.org" , "Prakash, Sathya" On Mon, 2008-07-28 at 13:01 -0600, Moore, Eric wrote: > On Sunday, July 27, 2008 11:56 PM, Matthew Wilcox wrote: > > > There has been some discussion recently (both on the mailing > > list and at > > OLS) of MSI and it reminded me of a perennial problem that I have with > > sym2. When interrupts don't work, I often get the bug > > reports, because > > the user seems sym2 spewing error messages right before the panic when > > it fails to mount their root filesystem. > > > > In my case, the MSI problem will manifest itself well before we bind > with the scsi midlayer. Meaning when there is a MSI problem, we > can't even bring up the card. Hence adding code in a eh_timed_out > callback handler would be meaningless in solving our problem. What I > need to do is find a problematic card, so I can verify some things. Actually, you don't need this. I verified the behaviour of the MSI problem simply by commenting out the request_irq. It looks like there's no simple way to simulate MSI misrouting, but perhaps I should look at that, since it would be useful. > My beliefs are that all the doorbell request at driver load time > work becuase we are polling with interrupts masked. This is the actual bug report: http://bugzilla.kernel.org/show_bug.cgi?id=11045 > The first command sent with interrupts enabled would be > SendPortEnable. If we have a timeout after calling > mpt_handshake_req_reply_wait, we resend the port enable with MSI > turned off, right? James