Bug#998718: Brasero fails (on Testing) burning an ISO image on a CD-RW

[Thomas Schmitt]

Hi,

the spoiled ASUS drive does not seem to be a direct result of an attempt
to read audio CD sectors from a data CD.
The drive is rather too tolerant in that aspect. The MMC-5 specs say
that it should throw error 5,64,00 "ILLEGAL MODE FOR THIS TRACK", but
the drive doesn't.

It does not go bad either.
So my nice theory about READ CD causing the SCSI error about unaligned
writing is officially dead.

And i have an unexpected casualty to bemoan ...

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Experiments made:

I removed the security barrier in cdrskin which prevents reading of
data CDs as audio CDs and told it to read a CD with data as audio:

  mkdir audio_test

  cdrskin -V -v dev=/dev/sr0 extract_audio_to=audio_test \
    >audio_test/scsi_log 2>&1

Normally it says:

  cdrskin: WARNING : Track 01 is not an audio track.
  cdrskin: SORRY : Medium in drive is not an audio CD.

but now it reads to my big surprise the whole track into file
audio_test/01.wav .

The scsi_log shows READ CD commands which demand CD-DA sectors and get
data back without error indication:

  READ CD
  be 04 00 00 00 00 00 00 18 10 00 00
     841123 us     [ 4002657 ]

The resulting file is too large, because CD-ROM checksums and other
non-data parts of the CD sectors where read together with the CD-ROM
payload data. Divided by 2352 the number of read bytes gives the
number of sectors of the track as announced by the CD table-of-content.

To prove that the specs are normally obeyed, i insert the same CD into
the TSSTcorp drive at /dev/sr2 and execute the cdrskin command (without
option -V because i need no SCSI log). The drive takes duely offense:

  cdrskin: Writing audio track file: audio_test/01.wav
  cdrskin: SORRY : SCSI error on read_cd(0,0): [5 64 00] Illegal request. Illegal mode for this track.
  cdrskin: SORRY : SCSI error on read_cd(0,0): [5 64 00] Illegal request. Illegal mode for this track.

but next the device file vanishes

  cdrskin: FAILURE : Failure to read audio sectors
  cdrskin: FATAL : Failed to transfer command to drive
  cdrskin: ( Most recent system error: 19  'No such device' )
  cdrskin: FATAL : --- SG_IO: return= -1 , errno= 19 , host_status= 0x0 , driver_status= 0x0
  cdrskin: FATAL : Attempted command: TEST UNIT READY : 00 00 00 00 00 00
  cdrskin: FATAL : Lost connection to drive

dmesg reports of repeated USB disconnect and connect going on.
No power cycle helps. It seems that the USB hub went mad. Unplugging and
replugging it into another mainboard USB port does not help.
A very unexpected victim of a drive and media experiment.

The drive comes back to life after i removed the hub and plugged the
drive's USB box cable directly into the mainboard USB port.

Violating SCSI specs brings bad luck. I won't ever repeat this test.
(I am not superstitious, because superstition brings even more bad luck.)

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Have a nice day :)

Thomas