From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH] libata: increase LBA48 max sectors to 65535 Date: Mon, 20 Feb 2006 06:25:12 -0500 Message-ID: <43F9A718.1060008@pobox.com> References: <1139754779159-git-send-email-htejun@gmail.com> <43EF8E61.5040409@pobox.com> <43EFD73D.4070207@gmail.com> <43F011DF.6020203@pobox.com> <20060215072449.GA31691@htj.dyndns.org> <20060215130725.GP4203@suse.de> <43F342E6.9060909@gmail.com> <20060215151200.GW4203@suse.de> <43F38D49.4080601@pobox.com> <20060216074258.GF4203@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail.dvmed.net ([216.237.124.58]:1492 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S932577AbWBTLZX (ORCPT ); Mon, 20 Feb 2006 06:25:23 -0500 In-Reply-To: <20060216074258.GF4203@suse.de> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jens Axboe Cc: Tejun Heo , albertcc@tw.ibm.com, linux-ide@vger.kernel.org, Mark Lord Jens Axboe wrote: > On Wed, Feb 15 2006, Jeff Garzik wrote: > >>Jens Axboe wrote: >> >>>On Thu, Feb 16 2006, Tejun Heo wrote: >>> >>> >>>>Jens Axboe wrote: >>>> >>>> >>>>>On Wed, Feb 15 2006, Tejun Heo wrote: >>>>> >>>>> >>>>> >>>>>>max_hw_sectors/max_sectors separation patch made into the tree, >>>>>>increase max_sectors to its hardware limit. >>>>>> >>>>>>Signed-off-by: Tejun Heo >>>>>> >>>>>>--- >>>>>> >>>>>>Jeff, first of all, thanks for the pointer. I have two more >>>>>>questions. >>>>>> >>>>>>* I make ATA_MAX_SECTORS_LBA48 65535 (the 0000h case is supposed to be >>>>>>broken, right?); however, the comment says 65534. Should it be >>>>>>65534? >>>>> >>>>> >>>>>Since we never noticed any breakage on !sectors on lba28, I think we can >>>>>safely assume that !sectors will work fine for lba48 as well. So why not >>>>>just make it full 64k, eg 65536? ->max_hw_sectors is an unsigned int >>>>>now, so 64k wont overflow it. >>>>> >>>> >>>>Hello, Jens. >>>> >>>>libata currently sets max_sectors to 200 (ATA_MAX_SECTORS) on lba28. >>>>Are you talking about IDE driver? IDE driver seems to set max_sectors >>>>to 256 on probe and make it 2048 while setting up ide disk if lba48. >>> >>> >>>Yes I mean the IDE driver. The 200 sector value in libata has always >>>struck me as being extremely odd and a very bad choice. It's somewhere >>>in between reasonable defaults, which isn't very nice. I'd suggest just >>>making it 256 as well, unless Jeff has a reason why it's set to 200. >> >>Its set to 200 for a libata-related reason that I now forget :( > > > Tsk tsk :-) > > >>It had nothing to do with controllers or devices, hence the FIXME. > > > How about making it 256 at the start of a kernel cycle and see if > anything falls apart? If IDE works, then surely SATA should as well. As I said, it had nothing to do with hardware. The variable in the equation is the driver code itself, so IDE working implies nothing here, alas. Sigh... I'll search through some old emails. Jeff