From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264235AbTEGTTK (ORCPT ); Wed, 7 May 2003 15:19:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264227AbTEGTTH (ORCPT ); Wed, 7 May 2003 15:19:07 -0400 Received: from ns.virtualhost.dk ([195.184.98.160]:43415 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S264235AbTEGTSY (ORCPT ); Wed, 7 May 2003 15:18:24 -0400 Date: Wed, 7 May 2003 21:30:58 +0200 From: Jens Axboe To: Alan Cox Cc: Linus Torvalds , Bartlomiej Zolnierkiewicz , Linux Kernel Mailing List Subject: Re: [PATCH] 2.5 ide 48-bit usage Message-ID: <20030507193058.GT823@suse.de> References: <1052332148.3061.50.camel@dhcp22.swansea.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1052332148.3061.50.camel@dhcp22.swansea.linux.org.uk> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 07 2003, Alan Cox wrote: > On Mer, 2003-05-07 at 17:28, Linus Torvalds wrote: > > At least if I read the patch correctly, theer's no way for upper layers to > > say "I want 48-bit addressing" - it's just turned on automatically for > > high sectors (or big transfers). > > You read it incorrectly. The lower layers don't know about the issue at > all. The disk layer does mapping (conceptually like READ6/READ10/READ16 > in SCSI) > > Raw I/O and other drivers can still issue CHS LBA28 and LBA48 taskfiles. > > > Well, you can mark the drive itself as wanting 48-bit transfers, but you > > can't do it on a per-request basis. > > Its per request at the low level. Thanks Alan, that is exactly right of course. Linus has one point (I'll give him that), in that it might be beneficial to be able to say "48-bit always on" for fs requests. Ie exactly what ide-disk currently does. -- Jens Axboe