From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH] pata_ali: Lots of problems still showing up with small ATAPI DMA Date: Wed, 28 Nov 2007 20:26:47 +0900 Message-ID: <474D5077.3090203@gmail.com> References: <20071119143758.3c6b85ee@the-village.bc.nu> <474CC60F.9040807@gmail.com> <20071128092518.5f2ca7df@the-village.bc.nu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from ro-out-1112.google.com ([72.14.202.178]:46663 "EHLO ro-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757617AbXK1L0z (ORCPT ); Wed, 28 Nov 2007 06:26:55 -0500 Received: by ro-out-1112.google.com with SMTP id p4so2416501roc for ; Wed, 28 Nov 2007 03:26:54 -0800 (PST) In-Reply-To: <20071128092518.5f2ca7df@the-village.bc.nu> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: jeff@garzik.org, akpm@osdl.org, linux-ide@vger.kernel.org Alan Cox wrote: > On Wed, 28 Nov 2007 10:36:15 +0900 > Tejun Heo wrote: > >> Alan Cox wrote: >>> Hopefully there is a better long term solution but for now lets favour >>> reliability. >> I'm getting a lot of reports on pata_ali w/ misc ATAPI commands too. Do >> you know whether it's a controller problem or drive one? All the >> reports I got are laptops and I can't really ask them to disassemble >> their laptops. :-) > > ALi is one that most definitely appears to be controller related. Thats > why I sent Jeff a patch to use DMA for 2K+ transfers only. Some ALi also > required the patch to set the xfer lengths. > > Its only some revs/combinations annoyingly - a lot of them (including the > ones I have direct access too) just work. Does READ_CD work fine via DMA? 2K+ filtering filters most if not all misc commands so usually only sector (2K) aligned READ and WRITEs are done via DMA. Interesting exceptions are READ_CD[_MSF] and READ/WRITE_BUFFER which usually exceed 2K but aren't aligned to 2K. I guess it's about time to write a test case program which issues a bunch of problematic commands and see which works. Thanks. -- tejun