Bug#573145: dd if=/dev/sr0 does not wait until media is loaded and ready

["Thomas Schmitt" <scdbackup@gmx.net>]

Package: linux-2.6
Version: 2.6.26-21
Severity: normal

Hi,

i experience with eSATA and USB failures to read
DVD+RW if the drive tray gets loaded automatically
or if it is still blinking from ongoing loading.

E.g. with dd:

  $ dd if=/dev/sr0 of=/dev/null bs=2048 count=1
  dd: opening `/dev/sr0': No medium found
  $

dmesg shows no related entries.

It does not help to load the tray explicitely

  $ eject -t /dev/sr0 && \
    dd if=/dev/sr0 of=/dev/null bs=2048 count=1
  dd: opening `/dev/sr0': No medium found
  $

But short time later it is well possible to read

  $ dd if=/dev/sr0 of=/dev/null bs=2048 count=1
  1+0 records in
  1+0 records out
  2048 bytes (2.0 kB) copied, 0.0684895 s, 29.9 kB/s
  $

The system was installed via
debian-504-amd64-netinst.iso.

  $ uname -a
  Linux debian 2.6.26-2-amd64 #1 SMP
  Tue Jan 12 22:12:20 UTC 2010 x86_64 GNU/Linux


Reading with autoloading still works with an IDE
drive at /dev/hda.

Burn programs have no problem with autoloading
on the affected USB/eSATA drive.


Have a nice day :)

Thomas