ATAPI Problems

I have had this problem with my DVD drive since 5.3RC1.  I 
just installed 6-LATEST hoping that the problem may have 
been corrected, but no such luck.

A normal boot of the GENERIC kernel gives these messages:

acd0: FAILURE - MODE_SENSE_BIG timed out
acd0: FAILURE - MODE_SENSE_BIG timed out
acd0: FAILURE - MODE_SENSE_BIG timed out
acd0: FAILURE - MODE_SENSE_BIG timed out
acd0: FAILURE - MODE_SENSE_BIG timed out
acd0: CDROM <NEC DVD+RW ND-1100A/10GE> at ata1-master UDMA33
acd0: FAILURE - TEST_UNIT_READY timed out
acd0: FAILURE - PREVENT_ALLOW timed out
acd0: FAILURE - TEST_UNIT_READY timed out
acd0: FAILURE - TEST_UNIT_READY timed out
acd0: FAILURE - PREVENT_ALLOW timed out
acd0: FAILURE - TEST_UNIT_READY timed out
acd0: FAILURE - PREVENT_ALLOW timed out
acd0: FAILURE - TEST_UNIT_READY timed out
acd0: FAILURE - TEST_UNIT_READY timed out
acd0: FAILURE - PREVENT_ALLOW timed out
acd0: FAILURE - TEST_UNIT_READY timed out
acd0: FAILURE - PREVENT_ALLOW timed out
acd0: FAILURE - TEST_UNIT_READY timed out
acd0: FAILURE - TEST_UNIT_READY timed out
acd0: FAILURE - PREVENT_ALLOW timed out

Afterwards, I am unable to mount a CD.  I receive several 
more of the same "timed out" messages, followed 
by "Input/output error" message when running 'mount /cdrom'.

If I run 'atacontrol mode 1 BIOSPIO BIOSPIO' (DVD drive is 
only drive on second ata channel), I receive one

acd0: FAILURE - TEST_UNIT_READY timed out

message and then the drive will mount normally.


Also, if I boot verbosely, my dmesg shows this:

acd0: <NEC DVD+RW ND-1100A/10GE> CDRW drive at ata1 as master
acd0: read 6890KB/s (6890KB/s) write 2755KB/s (2755KB/s), 2048KB buffer, PIO4
acd0: Reads: CDR, CDRW, CDDA stream, DVDROM, DVDR, packet
acd0: Writes: CDR, CDRW, test write, burnproof
acd0: Audio: play, 256 volume levels
acd0: Mechanism: ejectable tray, unlocked
acd0: Medium: CD-R 120mm data disc

No errors and the drive will mount normally.

I have tried several combinations of slave/master on 
different ATA channels with the same results.  I have also 
tried booting with/without ACPI and with/without DMA 
(hw.ata.atapi_dma="0/1" in loader.conf) and combinations of 
the two.

Any ideas where else I can look to find the source of this 
problem?

Thanks,
-Matt