From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932329AbWBKPpF (ORCPT ); Sat, 11 Feb 2006 10:45:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932330AbWBKPpF (ORCPT ); Sat, 11 Feb 2006 10:45:05 -0500 Received: from webbox4.loswebos.de ([213.187.93.205]:18333 "EHLO webbox4.loswebos.de") by vger.kernel.org with ESMTP id S932329AbWBKPpE (ORCPT ); Sat, 11 Feb 2006 10:45:04 -0500 Date: Sat, 11 Feb 2006 16:44:48 +0100 From: Marc Koschewski To: Doug McNaught Cc: Marc Koschewski , Jan Engelhardt , Phillip Susi , linux-kernel@vger.kernel.org Subject: Re: CD-blanking leads to machine freeze with current -git Message-ID: <20060211154448.GE5721@stiffy.osknowledge.org> References: <58cb370e0601270837h61ac2b03uee84c0fa9a92bc28@mail.gmail.com> <20060210175848.GA5533@stiffy.osknowledge.org> <43ECE734.5010907@cfl.rr.com> <20060210210006.GA5585@stiffy.osknowledge.org> <43ED04E9.9040900@cfl.rr.com> <20060211152518.GB5721@stiffy.osknowledge.org> <87u0b5sybs.fsf@asmodeus.mcnaught.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87u0b5sybs.fsf@asmodeus.mcnaught.org> X-PGP-Fingerprint: D514 7DC1 B5F5 8989 083E 38C9 5ECF E5BD 3430 ABF5 X-PGP-Key: http://www.osknowledge.org/~marc/pubkey.asc X-Operating-System: Linux stiffy 2.6.16-rc2-marc-g25bf368b-dirty User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Doug McNaught [2006-02-11 10:35:19 -0500]: > Marc Koschewski writes: > > > The cdrecord man page says this: > > > > Setting the -immed flag will request the command to return > > immediately while the operation proceeds in background, making > > the bus usable for the other devices and avoiding the system > > freeze. This is an experimental feature which may work or > > not, depending on the model of the CD/DVD writer. A correct > > solution would be to set up a correct cabling but there seem > > to be notebooks around that have been set up the wrong way by > > the manufacturer. As it is impossible to fix this problem in > > notebooks, the -immed option has been added. > > > It how can the bus run the command sent on the device 'in the > >background' when it can only process _one_ request at a time? > > > > To me it sound like the foreground process (cdrecord) fork()s a > >process to blank the CD-RW. Clear. But you said the bus is not able > >to do so... I'm not getting this. > > Some CD writers are apparently able to release the bus while > blanking, allowing use of the bus by other devices. The 'immed' flag > tries to use this feature. fork() has nothing to do with it--he's > talking about the IDE command, not the cdrecord program. I just thought about fork() as Alan (surely and others) told the IDE bus cannot run several commands at a time. So fork() was the only left-over I could think of. I didn't know some devices can kinda 'detach' themselves as long as the blank is going on... Things are clear now. OK, more clear. Not clear. ;) Marc