From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: What's in libata-dev.git Date: Mon, 11 Sep 2006 19:21:11 +0400 Message-ID: <45057EE7.40607@ru.mvista.com> References: <20060911132250.GA5178@havoc.gtf.org> <45056627.7030202@ru.mvista.com> <450566A2.1090009@garzik.org> <450568F3.3020005@ru.mvista.com> <1157986974.23085.147.camel@localhost.localdomain> <45057651.8000404@garzik.org> <1157988513.23085.159.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from h155.mvista.com ([63.81.120.155]:5429 "EHLO imap.sh.mvista.com") by vger.kernel.org with ESMTP id S964842AbWIKPTA (ORCPT ); Mon, 11 Sep 2006 11:19:00 -0400 In-Reply-To: <1157988513.23085.159.camel@localhost.localdomain> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: Jeff Garzik , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, Andrew Morton , Linus Torvalds Hello. Alan Cox wrote: >>>drivers/ide. You might want to do 256 for SATA Jeff but please don't do >>>256 for PATA. Reading specs is too hard for some people ;) >>>Some drives abort the xfer, some just choked. >>Where in drivers/ide is it limited to 255? > Being a sensible sanity check it was removed, and that was a small > mistake. Some 2.4 also has a 256 limit and it broken various transparent > raid units, older Maxtors(1Gb or so), some IBM drives etc. Got fixed in > -ac but never in base. > The failure pattern is pretty ugly too, your box runs and runs and > eventually you get a linear 256 sector I/O and it all blows up, > sometimes. The IBM's abort the xfer but the maxtors may or may not get > it right (its as if half the firmware has the right test). So, this seems to have a long history... :-) I've also heard several years ago of the drives not getting anything over 128 sectors right, but those should be really brain-damaged... > We could perhaps do it by ATA version - 255 for ATA < 3 256 for ATA 3+, Wouldn't work, I'm afraid. That IBM drive is UltraATA/33, so no less than ATA-4... Well, after having referred to the ID data read from it, it's ATA-3 actually. > lots for LBA48 ? Thats assuming you can show 256 sectors is faster than > 255. I'd bet for normal I/O its unmeasurably small. > Alan WBR, Sergei