From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: cached PCS Date: Wed, 09 Aug 2006 20:12:27 +0900 Message-ID: <44D9C31B.6000901@gmail.com> References: <44D97F07.9000301@garzik.org> <44D9AF83.80507@gmail.com> <44D9B43A.9010807@garzik.org> <44D9B4BC.5050707@gmail.com> <44D9B87A.8020507@garzik.org> <44D9BB4B.9050602@gmail.com> <44D9BD06.5080103@garzik.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from wx-out-0506.google.com ([66.249.82.239]:28867 "EHLO wx-out-0506.google.com") by vger.kernel.org with ESMTP id S1030684AbWHILMc (ORCPT ); Wed, 9 Aug 2006 07:12:32 -0400 Received: by wx-out-0506.google.com with SMTP id s14so121756wxc for ; Wed, 09 Aug 2006 04:12:31 -0700 (PDT) In-Reply-To: <44D9BD06.5080103@garzik.org> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jeff Garzik Cc: "linux-ide@vger.kernel.org" , Keith Owens Jeff Garzik wrote: > Tejun Heo wrote: >> Jeff Garzik wrote: >>> Tejun Heo wrote: >>>> Jeff Garzik wrote: >>>>> Tejun Heo wrote: >>>>>> Jeff Garzik wrote: >>>>>>> can you resurrect your cached PCS patch? >>>>>>> >>>>>>> 2.6.18-rc didn't fix the ghost device and long boot delay >>>>>>> problems for everybody. >>>>>> >>>>>> The cached PCS patch was to fix device detection failure on some >>>>>> ICH5s where PCS is cleared while probing the first port. >>>>>> Remaining ghost device and long boot delay are fixed by honor-PCS >>>>>> patch. Do you want me to resurrect both? >>>>> >>>>> hrm. Maybe just honor-PCS? >>>> >>>> Yeap, we need to verify whether the less-jealous-PCS-update patch >>>> cured the ICH5 problem. >>> >>> If you are talking about the patch currently in 2.6.18-rc, I got >>> several ACKs that it fixed their problems. >>> >>> But OTOH, there was also >>> http://marc.theaimsgroup.com/?t=115346292700002&r=1&w=2 >> >> I was talking about bugzilla bug #6724. >> >> http://bugzilla.kernel.org/show_bug.cgi?id=6724 >> >> It was a weird case of ICH5 clearing PCS present bits while the first >> port is being probed. The clearing happens during actual probe, that >> is, the bits look okay till the end of the first prereset() but on >> entry to prereset() for the second port, enabled bits are gone. IIRC, >> bug#6724 is different from all other reports. >> >> I asked the reporter to test 2.6.18-rc4 and see whether the problem is >> gone with new PCS handling. I'm a bit skeptical about the result. If >> the problem remains with 2.6.18-rc4, we'll need that cached PCS to >> solve that particular case. >> >> BTW, do you know what Keith Owen's chipset was? > > (Keith CC'd) > > I didn't see lspci output, but it looks like ICH5 from his drivers/ide > dmesg output. > > Did you look at some of the other messages? He provided some debug > traces in follow-up messages. Yes, I have and I can't think of any other way than ignoring PCS to work around the problem. If we set IGNORE_PCS for ich5 sata then we can also forget about cached PCS which is for ich5 sata. But, we might see ghost device detection and accompanying long delays. For ich 6/7/8, your recent change and honor-pcs patch should do the job. For ICH5, well... Just set IGNORE_PCS and wait for bug reports? -- tejun