[Bug 1757030] Re: Lite-On DS8A1H Slimline fails to record dual layer DVD+R

[Thomas Schmitt]

Hi,

> With -tao option, xorrecord has no trouble at all.

I am out of ideas, for now.

> Is there an easy way to dump the raw commands before the one that
failed?

I am not aware whether the Linux kernel has a logging facility for
ioctl(SG_IO). That's the system call by which we perform the SCSI command
transactions.

xorrecord has option -V, which produces a log of the SCSI transactions.
Try:

  xorrecord -V dev=/dev/sr0 -inq 2>&1 | less

and see how it talks to the drive via SG_IO.
E.g.:

  INQUIRY
  12 00 00 00 24 00
  From drive: 36b
  05 80 05 32 5b 00 00 00 48 4c 2d 44 54 2d 53 54 42 44 44 56
  44 52 57 20 47 47 43 2d 48 32 30 4c 31 2e 30 33
      9390 us     [ 45683 ]

Command INQUIRY was sent. It consisted of 6 bytes "12 00 00 00 24 00".
The drive replied by 36 bytes. As cleartext one can read "HL-DT-ST",
"BDDVDRW GGC-H20L", "1.03".
The transaction lasted 9390 microseconds. Time elapsed since initial call
to libburn was 45683 microseconds.

The commands are specified in SCSI documents SPC, MMC, and SBC.

growisofs has no such logging facility. But back in 2009 i augmented a
local copy of it by logging functionality from libburn.

If you are interested, it's about 150 lines of code. Mostly one piece
which defines two methods. Plus two method calls in method transport().
You'd have to put that code into a local copy of dvd+rw-tools source and
build the programs from that.

Then i will possibly be able to make a new thory from such a (very verbose)
log.


> I feel that this is a bug in growisofs with this specific drive.

Well, i transplanted that logging facility because growisofs was able
to burn on a particular drive with 16x DVD speed, whereas libburn suffered
from periodic throughput weakness.
After i spent two days with the problem, the situation suddenly turned
around. growisofs stumbled, libburn became fluent. I never found out what
was wrong with that drive. It belonged to a user who wanted it back.

So to my experience: Yes, the drive is peculiar.
But the rest is still unclear.


Have a nice day :)

Thomas

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https://bugs.launchpad.net/bugs/1757030

Title:
  Lite-On DS8A1H Slimline fails to record dual layer DVD+R

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