From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: VIA AHCI NCQ [was: Re: Recent AHCI drivers do not work with VIA VT8251 controllers (regression in 2.6.19 from 2.6.18)] Date: Thu, 01 Feb 2007 10:20:59 +0900 Message-ID: <45C1407B.1000703@gmail.com> References: <20070130155355.GB12475@reddwarf.farnz.org.uk> <200701312034.36499.simon@farnz.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from nz-out-0506.google.com ([64.233.162.224]:13768 "EHLO nz-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161197AbXBABVV (ORCPT ); Wed, 31 Jan 2007 20:21:21 -0500 Received: by nz-out-0506.google.com with SMTP id s1so365639nze for ; Wed, 31 Jan 2007 17:21:21 -0800 (PST) In-Reply-To: <200701312034.36499.simon@farnz.org.uk> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Simon Farnsworth Cc: linux-ide@vger.kernel.org Simon Farnsworth wrote: > On Tuesday 30 January 2007 15:53, Simon Farnsworth wrote: >> Hello, >> >> I've got a VIA VT8251 AHCI controller, driving two Maxtor SATA disks. >> Under Linux 2.6.18.5, it works; using 2.6.19.1, it fails to work (bug >> report at http://bugzilla.kernel.org/show_bug.cgi?id=7589 - note that >> pci=nomsi does not fix things for me, as I still get no interrupts). >> > I've been going through 2.6.20-rc releases this evening. 2.6.20-rc7 resolves > my AHCI fault (although not the MSI problem); it looks like Tejun Heo's fix > to ahci_thaw() in a718728f9e40ec79c0879ec6509a54fee214f5b2 fixes things for > my setup. Yeah, that was my mistake spotted by Jeff. IRQ pending was never cleared properly so the controller couldn't raise it. > Of course, I'm now curious as to why NCQ is disabled on VIA AHCI controllers. > Is there a known hardware bug I should be wary of, or is it just a case of > being cautious due to the other issues with the VT8251 (in which case I'll > try enabling it and reporting back)? Yeap, there is a known NCQ problem with vt8251. Can't find the original bug report now tho. commit 71f0737b2889b86f774a94afaf1342c2c0d61cb5 tree e983d3f4c3fccad0679aa8ae18a0c3ce91bfafe7 parent 8fa29b23d9e0ef976dc578aab98297d4f24f70da author Tejun Heo 1150899168 +0900 committer Jeff Garzik 1151032959 -0400 [PATCH] ahci: disable NCQ support on vt8251 vt8251 chokes on NCQ commands. Two different disks from different vendors are showing the same symptom and it seems that the windows driver from via doesn't support NCQ either. Disable NCQ support on this controller for the time being. Signed-off-by: Tejun Heo Cc: Aalderd Bouwman Cc: Bastiaan Jacques Signed-off-by: Jeff Garzik -- tejun