From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Date: Wed, 07 Jan 2004 09:50:29 +0000 Subject: Re: removable media revalidation - udev vs. devfs or static /dev Message-Id: <20040107095029.GX3483@suse.de> List-Id: References: <200401012333.04930.arvidjaar@mail.ru> <20040103133749.A3393@pclin040.win.tue.nl> <20040103124216.GA31006@suse.de> <200401031905.31806.arvidjaar@mail.ru> <20040103175414.GX5523@suse.de> <20040107094321.GC21059@suse.de> In-Reply-To: <20040107094321.GC21059@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Olaf Hering Cc: Andrey Borzenkov , Andries Brouwer , Greg KH , linux-hotplug-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org On Wed, Jan 07 2004, Olaf Hering wrote: > On Sat, Jan 03, Jens Axboe wrote: > > > On Sat, Jan 03 2004, Andrey Borzenkov wrote: > > > > Is there really no way to get a media change notification from ZIP or > > > > JAZ drives? > > > > > > If anyone knows please tell me - I will put it into supermount ... > > > > > > AFAIK in case of SCSI this is impossible simply by virtue of protocol - SCSI > > > device is not initiator. So you need something to poll device for status. > > > That is usually done on device open except in this case you can't open > > > because you do not yet have handle. > > > > You could queue a media notification request for long periods of time, > > being completed by the drive when a media change happens. At least mmc > > allows for this, doubt anyone has ever done it. > > > > So yeah, poll... > > Poll how? "kmediachangethread"? Or polling in userland? The latter would > (probably) lead to endless IO errors. Not very good. No need to put it in the kernel, user space fits the bil nicely. I don't see how this would lead to IO errors? > If I understand the Darwin sources correctly, a polling is used. But I > havent looked hard how they do it. It's the only way to do it. -- Jens Axboe ------------------------------------------------------- This SF.net email is sponsored by: IBM Linux Tutorials. Become an expert in LINUX or just sharpen your skills. Sign up for IBM's Free Linux Tutorials. Learn everything from the bash shell to sys admin. Click now! http://ads.osdn.com/?ad_id78&alloc_id371&op=click _______________________________________________ Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net Linux-hotplug-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266156AbUAGJum (ORCPT ); Wed, 7 Jan 2004 04:50:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266159AbUAGJul (ORCPT ); Wed, 7 Jan 2004 04:50:41 -0500 Received: from ns.virtualhost.dk ([195.184.98.160]:28562 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S266156AbUAGJui (ORCPT ); Wed, 7 Jan 2004 04:50:38 -0500 Date: Wed, 7 Jan 2004 10:50:29 +0100 From: Jens Axboe To: Olaf Hering Cc: Andrey Borzenkov , Andries Brouwer , Greg KH , linux-hotplug-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: removable media revalidation - udev vs. devfs or static /dev Message-ID: <20040107095029.GX3483@suse.de> References: <200401012333.04930.arvidjaar@mail.ru> <20040103133749.A3393@pclin040.win.tue.nl> <20040103124216.GA31006@suse.de> <200401031905.31806.arvidjaar@mail.ru> <20040103175414.GX5523@suse.de> <20040107094321.GC21059@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040107094321.GC21059@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 07 2004, Olaf Hering wrote: > On Sat, Jan 03, Jens Axboe wrote: > > > On Sat, Jan 03 2004, Andrey Borzenkov wrote: > > > > Is there really no way to get a media change notification from ZIP or > > > > JAZ drives? > > > > > > If anyone knows please tell me - I will put it into supermount ... > > > > > > AFAIK in case of SCSI this is impossible simply by virtue of protocol - SCSI > > > device is not initiator. So you need something to poll device for status. > > > That is usually done on device open except in this case you can't open > > > because you do not yet have handle. > > > > You could queue a media notification request for long periods of time, > > being completed by the drive when a media change happens. At least mmc > > allows for this, doubt anyone has ever done it. > > > > So yeah, poll... > > Poll how? "kmediachangethread"? Or polling in userland? The latter would > (probably) lead to endless IO errors. Not very good. No need to put it in the kernel, user space fits the bil nicely. I don't see how this would lead to IO errors? > If I understand the Darwin sources correctly, a polling is used. But I > havent looked hard how they do it. It's the only way to do it. -- Jens Axboe