From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264092AbTEGRiB (ORCPT ); Wed, 7 May 2003 13:38:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264102AbTEGRiB (ORCPT ); Wed, 7 May 2003 13:38:01 -0400 Received: from ns.virtualhost.dk ([195.184.98.160]:23781 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S264092AbTEGRh7 (ORCPT ); Wed, 7 May 2003 13:37:59 -0400 Date: Wed, 7 May 2003 19:50:33 +0200 From: Jens Axboe To: Linus Torvalds Cc: Bartlomiej Zolnierkiewicz , Linux Kernel Subject: Re: [PATCH] 2.5 ide 48-bit usage Message-ID: <20030507175033.GR823@suse.de> References: <20030507173341.GP823@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 07 2003, Linus Torvalds wrote: > > On Wed, 7 May 2003, Jens Axboe wrote: > > > > > > And testing. In particular, you might want to test whether a device > > > properly supports 48-bit addressing, either from the kernel or from user > > > programs. > > > > For that, a forced 48-bit hwif->addressing inherited by drives will > > suffice. And I agree, we should have that. > > No no no. > > You definitely do NOT want to set "hwif->addressing" to 1 before you've > tested whether it even _works_. Well duh, of course not. Whether a given request is executed in 48-bit or not is a check that _includes_ drive capabilities too of course. > Imagine something like "hdparm" - other things are already in progress, > the system is up, and IDE commands are potentially executing concurrently. > What something like that wants to do is to send one request out to check > whether 48-bit addressing works, but it absolutely does NOT want to set > some interface-global flag that affects other commands. Then it just puts a taskfile request on the request queue and lets it reach the drive, nicely syncronized with the other requests. There's no need to toggle any special bits for that. > Only after it has verified that 48-bit addressing does work should it set > the global flag. Sounds fine. -- Jens Axboe