I am the developer of libburn which probably does the drive
related stuff for your Brasero.
In order to distinguish between a problem of Brasero's own
code and a problem of libburn, you could use one of my
command line applications of libburn called xorriso. This can be installed with
sudo apt-get install xorriso
as it does not automatically get installed with
libburn4 on Ubuntu.
A blank command would be (I assume your drive has address
xorriso -outdev /dev/sr0 -blank as_needed
Then obtain the state of drive and medium:
xorriso -outdev /dev/sr0 -toc
In case of success, xorriso should then report among other lines
Media status: is blank
If this succeeds, then Brasero's code is to blame, resp. the
system facilities by which it gets information about drive and
medium. (I cannot help with such problems.)
If above command fails to blank the medium, then you will have to
show me the messages of the blank attempt and the outcome of -toc run.
Probably we will have to obtain a log of the commands sent to the
drive and the replies which are received:
xorriso -scsi_log on -report_about ALL -outdev /dev/sr0 -blank as_needed 2>&1 | tee -i /tmp/xorriso.log
The log will be quite verbose. Thus above command catches a copy in
/tmp/xorriso.log. This file would then of interest for me.
Have a nice day :)