From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: jgarzik and max-sectors: out of memory Date: Sat, 27 May 2006 15:37:16 -0400 Message-ID: <4478AA6C.5070305@garzik.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:64398 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S1751082AbWE0ThV (ORCPT ); Sat, 27 May 2006 15:37:21 -0400 Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: "linux-ide@vger.kernel.org" Cc: Tejun Heo , Alan Cox , Mark Lord , Jens Axboe , Hannes Reinecke 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. 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. Jeff