burner blues

[Greg Richardson]

After looking for a solution to my problem on various lists and HOW-TOs, I'm 
finally forced to seek help from you kind folks. But I really did try to 
figure it out myself.

I have a TEAC CD-R55S SCSI burner (listed as supported by cdrecord) connected 
to the external SCSI bus of a Macintosh 7300 (Old-World) PPC. The drive is 
properly terminated and works well in Mac OS. I'm using a 2.4 kernel, 
cdrecord 1.10 (I've tried more recent versions) and mkisofs 1.14 to create 
iso files, which I can mount. The kernel is using the NCR 53c7.8xx 
lower-level driver for the external bus. 

dmesg mentions the drive:

scsi2 : 53C94 
  Vendor: TEAC      Model: CD-R55S           Rev: 1.0L 
  Type:   CD-ROM                             ANSI SCSI revision: 02

Attached scsi CD-ROM sr1 at scsi2, channel 0, id 0, lun 0

cdrecord -scanbus outputs:

Cdrecord 1.10 (powerpc-unknown-linux-gnu) Copyright (C) 1995-2001 Jörg 
Schilling 
Linux sg driver version: 3.1.22 
Using libscg version 'schily-0.5' 
scsibus1: 
        1,0,0   100) 'SEAGATE ' 'ST34555N        ' '0930' Disk 
        1,1,0   101) * 
        1,2,0   102) 'R.A.R.E.' ' RS3432H-FS     ' '4141' Disk 
        1,3,0   103) 'MATSHITA' 'CD-ROM CR-8012  ' '1.0g' Removable CD-ROM 
        1,4,0   104) * 
        1,5,0   105) * 
        1,6,0   106) * 
        1,7,0   107) * 
scsibus2: 
        2,0,0   200) 'TEAC    ' 'CD-R55S         ' '1.0L' Removable CD-ROM 
        2,1,0   201) * 
        2,2,0   202) * 
        2,3,0   203) * 
        2,4,0   204) * 
        2,5,0   205) * 
        2,6,0   206) * 
        2,7,0   207) *

But when I issue the following command: 
cdrecord -v -dummy speed=0 (or 2 or 4 or -1) dev=2,0,0 yadayada.iso

cdrecord proceeds normally until it attempts to fill the buffer, then spits 
out: 

cdrecord: No such device or address. Cannot send SCSI cmd via ioctl (a few 
hundred times)
Segmentation fault.

/var/log/messages reports: scsi: device set offline - command error recover 
failed: host 2 channel 0 id 0 lun 0,

The drive is then not seen by cdrecord -scanbus until I reboot the machine.

This has been driving me crazy, so any help or hints would be greatly 
appreciated.

Greg Richardson