From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bartlomiej Zolnierkiewicz Subject: Re: libata PATA support - work items? Date: Fri, 7 Jan 2005 00:07:34 +0100 Message-ID: <58cb370e050106150743d6271f@mail.gmail.com> References: <006301c4ee5c$49e6a230$95714109@tw.ibm.com> <41DB2781.7000203@pobox.com> <005701c4f3ce$37d56140$fb7f4109@tw.ibm.com> <1105044491.24187.268.camel@localhost.localdomain> Reply-To: Bartlomiej Zolnierkiewicz Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from wproxy.gmail.com ([64.233.184.203]:38924 "EHLO wproxy.gmail.com") by vger.kernel.org with ESMTP id S263102AbVAFXHg (ORCPT ); Thu, 6 Jan 2005 18:07:36 -0500 Received: by wproxy.gmail.com with SMTP id 67so159981wri for ; Thu, 06 Jan 2005 15:07:34 -0800 (PST) In-Reply-To: <1105044491.24187.268.camel@localhost.localdomain> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: Albert Lee , Jeff Garzik , IDE Linux , Doug Maxey On Thu, 06 Jan 2005 21:29:42 +0000, Alan Cox wrote: > On Iau, 2005-01-06 at 08:51, Albert Lee wrote: > > For the 1st item, > > - add PATA device errata/blacklist info > > Is there any detail or draft design idea available? > > There is a fair bit of code in drivers/ide. Most of it is handling drive > problems that occurred with early DMA drives and it uses the > model/firmware info in the ident string to match drives that claim to do > DMA but do not and drives that claim not to but can. > > The logic is fairly simple and the database is easily transported or > shared. It is fairly important because some of these old drives > corrupted data if used DMA. (see drivers/ide/ide-dma.c) > > For PIO problem drives where there is a need to keep PIO modes chosen > carefully then ide-lib has a list (ide_pio_blacklist) and the ide-io > code knows about pio modes and older style EIDE cycle timing reports > (ide_get_best_pio_mode) There was some rumor (?) that this blacklist was created on CMD640 controller programmed with wrong timings... BTW ide_get_best_pio_mode(), it is really misleading (i.e. recent PIO tuning bug in it821x.c). > IDE CD has some DMA blacklists for ATAPI but they should be viewed with > caution as many entries were due to a bug in our atapi implementation > that was fixed long ago. There is only a common DMA blacklist in ide-dma.c.