Re: [Qemu-devel] Do you have a use for a tester of virtio-scsi with CD drives ?

[Thomas Schmitt]

Hi,

now for DVD+R burning.

It works well if i avoid command RESERVE TRACK.

RESERVE TRACK shows similar effects as the failed DVD-RW DAO run,
resp. the failed CD SAO run: qemu gets stuck at 100 % CPU.
No failed ioctl is indicated by my printfs.


Details:

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

As with all DVD types, READ DISC STRUCTURE formats 0x04 and 0x11 block
until timeout.
I disable them for these tests.

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

Blank DVD+R

  $ xorriso -for_backup -scsi_log on -dev /dev/sr1 -add /usr/include --

makes the guest system block 11 seconds after
  RESERVE TRACK
  53 00 00 00 00 00 00 0f 30 00 

CPU 100 % , no life in SSH sessions.

After killing qemu, the drive is usable from the host system.
A track is reserved, no data were written.

I could write another track to it, by avoiding RESERVE TRACK.
But now libburn is lost in the woods. It wanted to close the session,
but the first empty track causes this to fail.

I will later have to try to write and close the first track.
For now the medium is spoiled.

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

New DVD+R. This time no RESERVE TRACK.
For that i have to avoid that xorriso learns the size of the session
in advance. Thus the cdrtools usage model: 

  $ xorriso -as mkisofs -graft-points /usr/include=/usr/include \
            --for_backup \
    | xorriso -as cdrecord dev=/dev/sr1 -v -V -waiti -multi -

This yields a readable track. I get a credible table-of-content.
MD5 sums of files match correctly.

Another session can be added cdrtools style.
All is well. Table-of-content is readable, MD5 sums match.

I add a third session, and order the medium to be closed, by omitting
cdrecord option -multi.
Works well. Passes all read checks.

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

Since BD-R are very similar to DVD+R, but much more expensive,
i will tomorrow only test the case without RESERVE TRACK.


Have a nice day :)

Thomas