Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750812AbWAKJz7 (ORCPT ); Wed, 11 Jan 2006 04:55:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751427AbWAKJz7 (ORCPT ); Wed, 11 Jan 2006 04:55:59 -0500 Received: from ns.virtualhost.dk ([195.184.98.160]:65369 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S1750812AbWAKJz7 (ORCPT ); Wed, 11 Jan 2006 04:55:59 -0500 Date: Wed, 11 Jan 2006 10:55:07 +0100 From: Jens Axboe To: Andrey Borzenkov Cc: Chuck Ebbert <76306.1226@compuserve.com>, linux-kernel Subject: Re: [PATCH]trivial: add CDC_RAM to ide-cd capabilities mask Message-ID: <20060111095506.GV3389@suse.de> References: <20060111092937.GS3389@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 Content-Length: 2560 Lines: 73 On Wed, Jan 11 2006, Andrey Borzenkov wrote: > > > -----Original Message----- > From: Jens Axboe > To: Andrey Borzenkov > Date: Wed, 11 Jan 2006 10:29:38 +0100 > Subject: Re: [PATCH]trivial: add CDC_RAM to ide-cd capabilities mask > > > > > On Wed, Jan 11 2006, Andrey Borzenkov wrote: > > > > > > > > > > drive name: sr0 > > > > drive speed: 1 > > > > drive # of slots: 1 > > > > Can close tray: 1 > > > > Can open tray: 1 > > > > Can lock tray: 1 > > > > Can change speed: 0 > > > > Can select disk: 0 > > > > Can read multisession: 1 > > > > Can read MCN: 1 > > > > Reports media changed: 1 > > > > Can play audio: 1 > > > > Can write CD-R: 0 > > > > Can write CD-RW: 0 > > > > Can read DVD: 0 > > > > Can write DVD-R: 0 > > > > Can write DVD-RAM: 0 > > > > Can read MRW: 1 > > > > Can write MRW: 1 > > > > Can write RAM: 1 > > > > > > > > There's no way this drive knows anything about MRW or random-access writing: > > > > > > > ... > > > > And an ATAPI DVD-ROM also reports (before the above patch): > > > > > > > > Can read MRW: 1 > > > > Can write MRW: 1 > > > > Can write RAM: 1 > > > > > > > > > > I know. There were patches from Jens for both 2.4 and 2.6 that add MRW > > > support to ide-cd for sure; may be for sr too, am not sure. Jens, any > > > reasons for them not in mainstream? Otherwise probably ide-cd and sr should > > > not announce MRW capabiliies at all, it is too confusing; I'll send a patch > > > when I am at home. > > > > MRW support is in 2.6 since ages. The MRW flag is only detected on open, > > so it should disappear from the proc file once you have opened the > > drive. It has to be done that way, I'm afraid. > > > > I see, it is in generic cdrom code, sorry. > > is it possible that drive supports MRW_W without supporting any other write > method (_R/_RW)? Should not ide-cd/sr - or possibly even cdrom - mask MRW_W > if they do not support writing at all? I don't know why anyone would make such a device, but of course it's possible. Masking MRW if the device can't write sounds like a safe enough bet, I'll take a patch :) -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/