From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261441AbULAVQZ (ORCPT ); Wed, 1 Dec 2004 16:16:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261450AbULAVQZ (ORCPT ); Wed, 1 Dec 2004 16:16:25 -0500 Received: from ctb-mesg2.saix.net ([196.25.240.74]:31229 "EHLO ctb-mesg2.saix.net") by vger.kernel.org with ESMTP id S261441AbULAVQN (ORCPT ); Wed, 1 Dec 2004 16:16:13 -0500 Subject: Re: cdrecord dev=ATA cannont scanbus as non-root [u] From: "Martin Schlemmer [c]" Reply-To: Martin Schlemmer To: Jens Axboe Cc: "J.A. Magallon" , Jan Engelhardt , Lista Linux-Kernel In-Reply-To: <20041130071638.GC10450@suse.de> References: <1101763996l.13519l.0l@werewolf.able.es> <1101765555l.13519l.1l@werewolf.able.es> <20041130071638.GC10450@suse.de> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-M7PTssM+VTg6OG3tk1o9" Date: Wed, 01 Dec 2004 23:16:13 +0200 Message-Id: <1101935773.11949.86.camel@nosferatu.lan> Mime-Version: 1.0 X-Mailer: Evolution 2.0.2 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --=-M7PTssM+VTg6OG3tk1o9 Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Tue, 2004-11-30 at 08:16 +0100, Jens Axboe wrote: > On Mon, Nov 29 2004, J.A. Magallon wrote: > > dev=3DATAPI uses ide-scsi interface, through /dev/sgX. And: > >=20 > > > scsibus: -1 target: -1 lun: -1 > > > Warning: Using ATA Packet interface. > > > Warning: The related Linux kernel interface code seems to be unmainta= ined. > > > Warning: There is absolutely NO DMA, operations thus are slow. > >=20 > > dev=3DATA uses direct IDE burning. Try that as root. In my box, as root= : >=20 > Oh no, not this again... Please check the facts: the ATAPI method uses > the SG_IO ioctl, which is direct-to-device. It does _not_ go through > /dev/sgX, unless you actually give /dev/sgX as the device name. It has > nothing to do with ide-scsi. Period. >=20 > ATA uses CDROM_SEND_PACKET. This has nothing to do with direct IDE > burning, it's a crippled interface from the CDROM layer that should not > be used for anything. scsi-linux-ata.c should be ripped from the > cdrecord sources, or at least cdrecord should _never_ select that > transport for 2.6 kernels. For 2.4 you are far better off using > ide-scsi. >=20 > > The scan through ATA lasts much less than with ATAPI, and you can burn = with > > dev=3DATA:1,0,0 or dev=3D/dev/burner, which is the new recommended way. >=20 > No! ATAPI is the recommended way. >=20 Ok, so I am a bit confused here. We basically have 3 ways to use cdrecord on linux-2.6 without ide-scsi: 1) cdrecord dev=3D/dev/hdx 2) cdrecord dev=3DATA 3) cdrecord dev=3DATAPI Now, if I run all three and grep for '^Warning', I get: ----- $ cdrecord dev=3D/dev/cdrw -scanbus 2>&1 | grep '^Warning' Warning: Open by 'devname' is unintentional and not supported. $ cdrecord dev=3DATA -scanbus 2>&1 | grep '^Warning' Warning: Using badly designed ATAPI via /dev/hd* interface. $ cdrecord dev=3DATAPI -scanbus 2>&1 | grep '^Warning' Warning: Using ATA Packet interface. Warning: The related Linux kernel interface code seems to be unmaintained. Warning: There is absolutely NO DMA, operations thus are slow. $ ----- Which means: 1) dev=3D/dev/hdx - Open by 'devname' is unintentional and not supported. 2) dev=3DATA - Using badly designed ATAPI via /dev/hd* interface. 3) dev=3DATAPI - Using ATA Packet interface. (And some nice things about it not being maintained and slow) If I check the source for that, I get: ----- libscg $ grep "Open by 'devname' is unintentional and not supported." * scsi-linux-sg.c: "Warning: Open by 'devname' is unin= tentional and not supported.\n"); libscg $ grep 'Using badly designed ATAPI via /dev/hd\* interface.' * scsi-linux-sg.c: "Warning: Using badly desig= ned ATAPI via /dev/hd* interface.\n"); libscg $ grep 'Using ATA Packet interface.' * scsi-linux-ata.c: error("Warning: Using ATA Packet interface.= \n"); libscg # ----- Which hopefully (without really checking the source) means each are implemented in these source files: 1) dev=3D/dev/hdx - scsi-linux-sg.c 2) dev=3DATA - scsi-linux-sg.c 3) dev=3DATAPI - scsi-linux-ata.c So if I take note of you comment above about scsi-linux-ata.c (or actually give a fart about Jorg's warning about unmaintained and slow), should ATA rather than ATAPI not be the recommended way?? Also, how about having the kernel print a warning when the depreciated interface (ATAPI??) is used ?=20 Thanks, --=20 Martin Schlemmer --=-M7PTssM+VTg6OG3tk1o9 Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (GNU/Linux) iD8DBQBBrjSdqburzKaJYLYRAn21AJ9neiUifhUYJ54FSFb+qJ/OV0vdowCgkHTz fhrEAhpnT//O5Du0W9qwASs= =OOmu -----END PGP SIGNATURE----- --=-M7PTssM+VTg6OG3tk1o9--