Something odd is going on with this.  After the HAL crash in the last note I
restarted HAL and the drive was working again.  I mounted and ejected several
CDs in different formats and everything worked as normal.  A sample log entry was:

Feb  5 10:08:27 bilin1 kernel: UDF-fs: Partition marked readonly; forcing
readonly mount
Feb  5 10:08:27 bilin1 kernel: UDF-fs INFO UDF 0.9.8.1 (2004/29/09) Mounting
volume 'Roxio4', timestamp 2006/11/30 11:27 (1000)
Feb  5 10:08:27 bilin1 gnome-keyring-daemon[13094]: adding removable location:
volume_label_Roxio4 at /media/Roxio4
Feb  5 10:08:27 bilin1 hald: mounted /dev/sr0 on behalf of uid 13779

I then restarted the server and inserted a CD, and am back to the errors like:

Feb  5 10:21:47 bilin1 kernel: ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0
action 0x2 frozen
Feb  5 10:21:47 bilin1 kernel: ata1.00: cmd a0/01:00:00:00:00/00:00:00:00:00/a0
tag 0 cdb 0x28 data 131072 in
Feb  5 10:21:47 bilin1 kernel:          res 40/00:02:00:0c:00/00:00:00:00:00/a0
Emask 0x4 (timeout)
Feb  5 10:21:47 bilin1 kernel: ata1: soft resetting port
Feb  5 10:21:47 bilin1 kernel: ata1.00: configured for UDMA/25
Feb  5 10:21:47 bilin1 kernel: ata1: EH complete
Feb  5 10:22:17 bilin1 kernel: ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0
action 0x2 frozen
Feb  5 10:22:17 bilin1 kernel: ata1.00: cmd a0/01:00:00:00:00/00:00:00:00:00/a0
tag 0 cdb 0x28 data 131072 in
Feb  5 10:22:17 bilin1 kernel:          res 40/00:02:00:0c:00/00:00:00:00:00/a0
Emask 0x4 (timeout)
Feb  5 10:22:17 bilin1 kernel: ata1: soft resetting port
Feb  5 10:22:18 bilin1 kernel: ata1.00: configured for UDMA/25
Feb  5 10:22:18 bilin1 kernel: ata1: EH complete
Feb  5 10:22:48 bilin1 kernel: ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0
action 0x2 frozen
Feb  5 10:22:48 bilin1 kernel: ata1.00: cmd a0/01:00:00:00:00/00:00:00:00:00/a0
tag 0 cdb 0x28 data 131072 in
Feb  5 10:22:48 bilin1 kernel:          res 40/00:02:00:0c:00/00:00:00:00:00/a0
Emask 0x4 (timeout)
Feb  5 10:22:48 bilin1 kernel: ata1: soft resetting port
Feb  5 10:22:48 bilin1 kernel: ata1.00: configured for UDMA/25
Feb  5 10:22:48 bilin1 kernel: ata1: EH complete
Feb  5 10:23:18 bilin1 kernel: ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0
action 0x2 frozen
Feb  5 10:23:18 bilin1 kernel: ata1.00: cmd a0/01:00:00:00:00/00:00:00:00:00/a0
tag 0 cdb 0x28 data 131072 in
Feb  5 10:23:18 bilin1 kernel:          res 40/00:02:00:0c:00/00:00:00:00:00/a0
Emask 0x4 (timeout)
Feb  5 10:23:18 bilin1 kernel: ata1: soft resetting port
Feb  5 10:23:19 bilin1 kernel: ata1.00: configured for UDMA/25
Feb  5 10:23:19 bilin1 kernel: sr 2:0:0:0: [sr0] Result: hostbyte=DID_OK
driverbyte=DRIVER_SENSE,SUGGEST_OK
Feb  5 10:23:19 bilin1 kernel: sr 2:0:0:0: [sr0] Sense Key : Aborted Command
[current] [descriptor]
Feb  5 10:23:19 bilin1 kernel: Descriptor sense data with sense descriptors (in
hex):
Feb  5 10:23:19 bilin1 kernel:         72 0b 00 00 00 00 00 0e 09 0c 00 00 00 02
00 00 
Feb  5 10:23:19 bilin1 kernel:         00 0c 00 00 a0 40 
Feb  5 10:23:19 bilin1 kernel: sr 2:0:0:0: [sr0] Add. Sense: No additional sense
information
Feb  5 10:23:19 bilin1 kernel: end_request: I/O error, dev sr0, sector 232
Feb  5 10:23:19 bilin1 kernel: printk: 30 messages suppressed.
Feb  5 10:23:19 bilin1 kernel: Buffer I/O error on device sr0, logical block 29
Feb  5 10:23:19 bilin1 kernel: Buffer I/O error on device sr0, logical block 30
Feb  5 10:23:19 bilin1 kernel: Buffer I/O error on device sr0, logical block 31
Feb  5 10:23:19 bilin1 kernel: Buffer I/O error on device sr0, logical block 32
Feb  5 10:23:19 bilin1 kernel: Buffer I/O error on device sr0, logical block 33
Feb  5 10:23:19 bilin1 kernel: Buffer I/O error on device sr0, logical block 34
Feb  5 10:23:19 bilin1 kernel: Buffer I/O error on device sr0, logical block 35
Feb  5 10:23:19 bilin1 kernel: Buffer I/O error on device sr0, logical block 36
Feb  5 10:23:19 bilin1 kernel: Buffer I/O error on device sr0, logical block 37
Feb  5 10:23:19 bilin1 kernel: Buffer I/O error on device sr0, logical block 38
Feb  5 10:23:19 bilin1 kernel: ata1: EH complete

I tried restarting HAL again but it made no difference.

Looking at my yum.log there have been no HAL or kernel changes since the machine
was last rebooted so I'm at a loss to explain what was different this time.