Problem with CDRW drives, SCSI emulation and devfs

Tarball

Hi,

In my machine I have a DVD-Rom drive and a CDRW drive.
DVD-Rom - /dev/hdb
CDRW - /dev/hdc

During boot the IDE-SCSI module loads and displays the following:
--------- 8< snip 8< -----------------
SCSI subsystem driver Revision: 1.00
scsi0 : SCSI host adapter emulation for IDE ATAPI devices
Vendor: LG Model: DVD-ROM DRD8160B Rev: 1.00
Type: CD-ROM ANSI SCSI revision: 02
Vendor: SONY Model: CD-RW CRX1611 Rev: TYS3
Type: CD-ROM ANSI SCSI revision: 02
Attached scsi CD-ROM sr0 at scsi0, channel 0, id 0, lun 0
Attached scsi CD-ROM sr1 at scsi0, channel 0, id 1, lun 0
sr0: scsi3-mmc drive: 0x/48x cd/rw xa/form2 cdda tray
Uniform CD-ROM driver Revision: 3.12
sr1: scsi3-mmc drive: 40x/40x writer cd/rw xa/form2 cdda tray
--------- 8< snip 8< -----------------

Yet when the system is loaded, the devices in /dev/... are:

/dev/hdb (DVD) - /dev/scsi/host0/bus0/target1/lun0/cd
/dev/hdc (CDRW)- /dev/scsi/host0/bus0/target0/lun0/cd

and therefore:

/dev/hdb (DVD) has symlinks: /dev/sr1 & /dev/sg1
/dev/hdc (CDRW) has symlinks: /dev/sr0 & /dev/sg0

But if I run 'cdrecord -scanbus' it produces the following:
natty ~ # cdrecord -scanbus
Cdrecord 1.11a24 (i686-pc-linux-gnu) Copyright (C) 1995-2002 Jörg Schilling
Linux sg driver version: 3.1.22
Using libscg version 'schily-0.6'
scsibus0:
0,0,0 0) 'LG ' 'DVD-ROM DRD8160B' '1.00' Removable CD-ROM
0,1,0 1) 'SONY ' 'CD-RW CRX1611 ' 'TYS3' Removable CD-ROM
0,2,0 2) *
0,3,0 3) *
0,4,0 4) *
0,5,0 5) *
0,6,0 6) *
0,7,0 7) *

So, if I am trying to use 'gtoaster' to write a CD I select the second drive as the writer (the Sony drive, dev=0,1,0) but when gtoaster tries to actually write to dev=0,1,0 it seems to be the DVD drive that is accesses (and obviously fails!)

Any ideas what is going on?? I've only had the problem since moving to Gentoo but then this is the first time I have used devfs.
All the IDE-SCSI stuff is compiled into the kernel.

Cheer.
----------------------------------
Abit BP6 MoBo (2x 466 Celerons)
640MB RAM
1x10GB Maxtor drive, 1x40GB Maxtor
Abit Siluro GeForce 3 Ti200
LG DVD-ROM drive
Sony CDRW drive.

smtanner · Posted: Tue Jun 25, 2002 4:23 am Post subject:

What happens if you physically reverse the drives on your motherboard:

hdb = cdrw
hdc = dvd

Do you still have the same problem?

I know that is not the best solution but for lack of anything else.

What do you have attached as hda?

Anything attached as hdd?

Tarball · Posted: Tue Jun 25, 2002 10:25 am Post subject:

I haven't tried reversing the drives.

On hda I have a 10GB Maxtor HD and there is nothing on hdd.
The only gripe I have about reversing the DVD and CDRW drives is that the CDRW drive would have to be a slave.

At the moment I have the SCSI emulation stuff compiled into the kernel. I am gonna recompile the stuff as modules then I can try playing around with it on the command-line.

How are the devices 'realised' by devfs. Is it just a first come first served basis???

Cheers.

smtanner · Posted: Tue Jun 25, 2002 1:11 pm Post subject:

Not sure how devices are itialized with devfs.

Try disabling devfs to see what happens. In grub, use the line devfs=nomunt. I think it is the same in lilo. If this fixes your problem, then it would seem to be a bug in devfs.