From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: jgarzik and max-sectors: out of memory Date: Sat, 27 May 2006 22:43:41 +0200 Message-ID: <200605272243.41832.axboe@suse.de> References: <4478AA6C.5070305@garzik.org> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from ns.virtualhost.dk ([195.184.98.160]:35926 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S964959AbWE0Upz (ORCPT ); Sat, 27 May 2006 16:45:55 -0400 In-Reply-To: <4478AA6C.5070305@garzik.org> Content-Disposition: inline Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jeff Garzik Cc: "linux-ide@vger.kernel.org" , Tejun Heo , Alan Cox , Mark Lord , Hannes Reinecke On Saturday 27 May 2006 21:37, Jeff Garzik wrote: > ATA_MAX_SECTORS is 200, rather than than 256 like it should be. I seem > to recall that this was due to libata being incomplete in some area, but > I've tried in vain for a year to remember where the alleged > incompleteness was, to no avail. So, my brain is out of memory :) > > Further -- someone with a long ATA memory correct me -- I think that we > can increase ATA_MAX_PRD beyond 256. Most DMA engines should just keep > chugging along, provided that we continue to respect the 64k IDE DMA > boundaries. The PRD count is much less of a problem. > So, I propose that we rename ATA_MAX_SECTORS to ATA_LBA28_SECTORS, and > change its value to 256, and see what happens. People have reported > that that worked for them, so let's subject it to a wide test. If > people are extremely paranoid, we could increase it to 255, and then in > the next kernel version, bump it from 255 to 256. > > Then we can look at increasing ATA_MAX_PRD, if that's feasible for PATA > hardware. Yep lets please do that, I don't think libata ever had any problems with 256 sectors other than perhaps a worry that it would break "something" :-) Jens