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

[Thomas Schmitt]

Hi,

Mauro Sacchetto wrote:
> sg_raw /dev/sr0 be 00 ff ff ff ff 00 00 01 10 00 00 --outfile=tdb_data.bin
> After this, the drive is unavailable

Well, then we have found:

- The immediate cause of the problem: READ CD with LBA -1.

- A good suspect in Brasero: Function brasero_medium_track_written_SAO()
    https://sources.debian.org/src/brasero/3.12.3-1/libbrasero-media/brasero-medium.c/?hl=1565#L1565

- The generally problematic expectation of Brasero that it can determine
  whether a CD track was written by write type SAO (and not by TAO).

-----------------------------------------------------------------------------

We have not explored yet:

- Why does Brasero believe to see 2 tracks on a closed CD-RW with a
  single TAO track ?
    BraseroMedia: (at brasero-medium.c:2062) 2 track(s) found
  This misperception triggers the call to brasero_medium_track_written_SAO().

- Why does brasero_medium_track_get_info() want to distinguish SAO from
  TAO only if its parameter multisession is set to "true". Its only caller
  has a strange comment before setting multisession:
    https://sources.debian.org/src/brasero/3.12.3-1/libbrasero-media/brasero-medium.c/?#L2052

	num = (size - sizeof (BraseroScsiFormattedTocData)) /
	       sizeof (BraseroScsiTocDesc);

        /* remove 1 for leadout */
	multisession = !(priv->info & BRASERO_MEDIUM_BLANK) && num > 0;

  If the leadout is counted as surplus track, then why not "num > 1" ?

-----------------------------------------------------------------------------

So the Brasero "Copy" task of TAO CDs is not possible with the ASUS drive.
The code of Brasero would have to be changed for that.

We have no workaround yet for the case of burning the netinst ISO by
Brasero.
I found no way to tell Brasero that its libburn plugin shall ask libburn
for SAO. libburn would of course be able to avoid SAO if it is told to do
so. It would propose SAO if being asked to find a suitable write type for
track input of which the size is known in advance.

My only idea which does not need a code change is to employ the wodim
plugin of Brasero and to hope that it burns by write type SAO.
If so, then the drive would not get lost after a successful burn run.

Of course you would have to carefully avoid to show Brasero a TAO CD in
the ASUS drive.
Best would be to blank any CD-RW before giving it to Brasero.

-----------------------------------------------------------------------------

Have a nice day :)

Thomas