USB/SCSI layer problem with CD Writer

From: James (rjm178_at_hotmail.com)
Date: 11/30/04 

Date: 30 Nov 2004 08:17:25 -0800

From: rjmullens@hotmail.com (James)
Newsgroups: comp.os.linux.hardware
Subject: USB/SCSI CD-Writer problem ("No medium found")
NNTP-Posting-Host: 222.149.255.187

Hi,

I have a CD-Writer connected via USB which Redhat won't even read as a
plain old CD-Rom drive.

It comes up ok in the usb and scsi subsystems, but I get a sense error
on boot:

   sr0: CDROM (ioctl) error, command: Test Unit Ready 00 00 00 00 00
   [valid=0] Info fld=0x0, Current sr00:00: sense key None
   cdrom: open failed

If I subsequently try to mount a cd, I get:

   mount -t iso9660 /dev/scd0 /mnt/cdrw
   mount: block device /dev/scd0 is write-protected, mounting
read-only
   mount: No medium found

Everything else seems to be ok (BTW it works ok under windows so I
know the device itself is ok).

My questions to anyone who can help:

1. What is the significance of the Sense Error in the dmesg dump
below?

2. Where do I go from here?

Any help would be greatly appreciated.

Regards

James

Other Details
================

Box: Old Vaio laptop with USB support
OS: Redhat 7 (yeah I know it's old, but I've kept it upgraded -
           still 2.2.16 kernel though)
CD drive: Buffalo USB (CDRW-48U2 model) Japanese

The device is recognised and appears in usbview
with entries in

- /proc/sys/dev/cdrom

  -rw-r--r-- 1 root root 0 Nov 30 04:25 autoclose
  -rw-r--r-- 1 root root 0 Nov 30 04:25 autoeject
  -rw-r--r-- 1 root root 0 Nov 30 04:25 check_media
  -rw-r--r-- 1 root root 0 Nov 30 04:25 debug
  -r--r--r-- 1 root root 0 Nov 30 04:25 info
  -rw-r--r-- 1 root root 0 Nov 30 04:25 lock

- /proc/bus/usb/devices

    T: Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 2 Spd=12 MxCh= 0
    D: Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1
    P: Vendor=0411 ProdID=0028 Rev= 1.01
    S: Manufacturer=MELCO INC.
    S: Product=MELCO INC. USB2-IDE Bridge
    S: SerialNumber=00000301B42C
    C:* #Ifs= 1 Cfg#= 1 Atr=c0 MxPwr= 2mA
    I: If#= 0 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50
Driver=usb-storage
    E: Ad=02(O) Atr=02(Bulk) MxPS= 64 Ivl= 1ms
    E: Ad=82(I) Atr=02(Bulk) MxPS= 64 Ivl= 0ms

- /proc/bus/usb/drivers
        usb-storage
         hid
         hub
         usbdevfs

- /proc/scsi/scsi
     Attached devices:
     Host: scsi0 Channel: 00 Id: 00 Lun: 00
     Vendor: HL-DT-ST Model: RW/DVD GCC-4521B Rev: 1.00
     Type: CD-ROM ANSI SCSI revision: 02

- /proc/scsi/usb/0
     Host scsi0: usb-storage
     Vendor: MELCO INC.
     Product: MELCO INC. USB2-IDE Bridge
     Serial Number: 00000301B42C
     Protocol: Transparent SCSI
     Transport: Bulk
          GUID: 04110028000000000301b42c

The other relevent bits from dmesg are:
  usb.c: registered new driver usbdevfs
  usb.c: registered new driver hub
  usb-uhci.c: $Revision: 1.232 $ time 16:53:56 Aug 22 2000
  usb-uhci.c: High bandwidth mode enabled
  usb-uhci.c: Intel USB controller: setting latency timer to 0
  usb-uhci.c: USB UHCI at I/O 0xfc60, IRQ 9
  usb-uhci.c: Detected 2 ports
  usb.c: new USB bus registered, assigned bus number 1
  usb.c: USB new device connect, assigned device number 1
  hub.c: USB hub found
  hub.c: 2 ports detected
  usb.c: USB new device connect, assigned device number 2
  usb.c: This device is not recognized by any installed USB driver.
  usb.c: USB new device connect, assigned device number 3
  usb.c: This device is not recognized by any installed USB driver.
  usb.c: registered new driver hid
  input0: USB HID v1.00 Mouse [Cypress Sem. Cypress USB Mouse] on
usb1:3.0
  mouse0: PS/2 mouse device for input0
  ...
  scsi singledevice 1 0 0 0
  usb.c: registered new driver usb-storage
  scsi0 : SCSI emulation for USB Mass Storage devices
  scsi : 1 host.
    Vendor: HL-DT-ST Model: RW/DVD GCC-4521B Rev: 1.00
    Type: CD-ROM ANSI SCSI revision: 02
  Detected scsi CD-ROM sr0 at scsi0, channel 0, id 0, lun 0
  sr0: scsi3-mmc drive: 0x/0x caddy
  Uniform CD-ROM driver Revision: 3.10
  WARNING: USB Mass Storage data integrity not assured
  USB Mass Storage device found at 2
  USB Mass Storage support registered.

and then:

  sr0: CDROM (ioctl) error, command: Test Unit Ready 00 00 00 00 00
  [valid=0] Info fld=0x0, Current sr00:00: sense key None
  cdrom: open failed.

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