ata2 errors with CDRW drive renders drive inaccessible

As dual boot, I've installed Ubuntu 7.04, Feisty Fawn, with recent
updates (Linux laptop 2.6.20-13-generic #2 SMP Sun Mar 25 00:21:25 UTC
2007 i686 GNU/Linux). I also have Fedora Core 5 for almost a year now, I
have no problems on FC5.

I'm happy with Ubuntu except a very annoying problem: I cannot blank or
record any CDs. Well, I was able to blank a CDRW, 2 out of 50 times,
which I consider by chance. For example, I run the command "wodim -v
dev=/dev/sr0 blank=fast", if wodim is going to fail (which is almost
each time), it spends a lot of time trying something, then spits out the
messages you can find below, and fails. When this happens I cannot
access to the CDRW/DVDROM drive anymore (wodim cannot find any
accessible CD drive, and I cannot use the CD drive even for reading). At
that point, since I don't know how to reinitialize the drive, I have to
reboot the system.

I tried many things, including downloading and installing the latest
version of the original cdrecord, to see if the problem is related with
wodim, but cdrecord behaves the same. I also tried some options and
different device names like /dev/sg1, /dev/cdrw, 1,0,0, etc., without
success. I've also set the environment variable CDR_NODMATEST, stopped
udevd and hald (to see if they interfere with wodim), etc., again
without success.

"wodim --devices" gives:
wodim: Overview of accessible drives (1 found) :
0 dev='/dev/sr0' rwrw-- : 'SAMSUNG' 'CDRW/DVD SN-308B'

Since I have no problems on FC5 using this same CD writer, I don't think
the issue is related with the hardware.

I tend to believe that this is probably related with the device drivers
on Ubuntu (just a wild guess). And another difference between Ubuntu and
FC5 is the SMP kernel (among many other differences of course).

Among other output messages, the following is what I see on the root
console:

ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0
ata2.00: (BMDMA stat 0x5)
ata2.00: cmd a0/01:00:00:00:00/00:00:00:00:00/a0 tag 0 cdb 0x5a data 2
in
ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0
ata2.00: (BMDMA stat 0x5)
ata2.00: cmd a0/01:00:00:00:00/00:00:00:00:00/a0 tag 0 cdb 0x5a data 8
in
ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x2 frozen
ata2.00: (BMDMA stat 0x4)
ata2.00: cmd a0/01:00:00:00:00/00:00:00:00:00/a0 tag 0 cdb 0x55 data 16
in
ata2.00: revalidation failed (errno=-2)
ata2.00: revalidation failed (errno=-2)
ata2.00: revalidation failed (errno=-2)
Errno: 5 (Input/output error), prevent/allow medium removal scsi
sendcmd: fatal error
CDB: 1E 00 00 00 00 00

Also, the messages log has the following lines when this error occurs:

Mar 29 12:21:01 laptop kernel: [ 4295.256000] ata2.00: 12 bytes trailing
data
Mar 29 12:21:01 laptop kernel: [ 4295.256000] res
51/51:03:00:00:00/00:00:00:00:00/a0 Emask 0x3 (HSM violation)
Mar 29 12:21:01 laptop kernel: [ 4295.256000] ata2: soft resetting port
Mar 29 12:21:02 laptop kernel: [ 4295.568000] ata2: failed to recover
some devices, retrying in 5 secs
Mar 29 12:21:07 laptop kernel: [ 4300.572000] ata2: soft resetting port
Mar 29 12:21:07 laptop kernel: [ 4300.884000] ata2: failed to recover
some devices, retrying in 5 secs
Mar 29 12:21:12 laptop kernel: [ 4305.888000] ata2: soft resetting port
Mar 29 12:21:12 laptop kernel: [ 4306.200000] ata2.00: disabled
Mar 29 12:21:13 laptop kernel: [ 4306.704000] ata2: EH complete

I guess the device ata2 fails to recover is the CD drive, and that's
probably why it becomes inaccessible after this error.

I tried cdrskin cd burner too, and after the first scan the device becomes inaccessible again, and cdrskin reports random characters as device name.

This issue may be related with a similar bug report and comments here: http://bugzilla.kernel.org/show_bug.cgi?id=8244#c15

I believe the issue is related with the new libata, but what could be the reason for these errors? Is there any fix? What can I do? Can I at least reinitialize the inaccessbile CD drive without a reboot?

Thanks,

ProblemType: Bug
Architecture: i386
Date: Fri Mar 30 16:27:39 2007
DistroRelease: Ubuntu 7.04
Uname: Linux laptop 2.6.20-13-generic #2 SMP Sun Mar 25 00:21:25 UTC 2007 i686 GNU/Linux