Panic in "irq15: ata1" (perhaps just ATAPICAM...?)

Okay, I can't exactly reproduce the orignal panic (I think -- these might
all be related), but here's another cdparanoia panic.  I am using ATAPICAM,
which I vaguely remember has caused some issues with other people.  Note
that this ocurred after I let bgfsck run its course.

First off, a 'dmesg | grep ata1':

    ata1: at 0x170 irq 15 on atapci0
    acd0: CDRW <SONY CD-RW CRX230E> at ata1-master PIO4
    acd1: DVDROM <Pioneer DVD-ROM ATAPIModel DVD-120S> at ata1-slave PIO4
    cd0 at ata1 bus 0 target 0 lun 0
    cd1 at ata1 bus 0 target 1 lun 0

Now the actual panic:

    Fatal trap 12: page fault while in kernel mode
    cpuod = 0; apic id = 00

    fault virtual address      = 0xc1cad220
    fault code                 = supervisor read, page not present
    instruction pointer        = 0x8:0xc049a4a9
    stack pointer              = 0x10:0xd42bac74
    frame pointer              = 0x10:0xd42baca8
    code segment               = base 0x0, limit 0xfffff, type 0x1b
                               = DPL 0, pres 1, def32 1, gran 1
    processor eflags           = interrupt enabled, resume, IOPL = 0
    current process            = 26 (irq15: ata1)

    kernel: type 12 trap, code=0
    Stopped at      ata_pio_read+0x64:         repe insw       %dx,%es:(%edi)
    db> examine
    ata_pio_read+0x64:      eb6d66f3
    db> trace
    ata_pio_read(c1ca5168,12,52e19674,d42bacdc,12) at ata_pio_read+0x64
    ata_generic_interrupt(c1a7d600,0,0,0,0) at ata_generic_interrupt+0x473
    ithread_loop(c19c2400,d42bad48,0,0,c19c2400) at ithread_loop+0x19c
    fork_exit(c05217c3,c19c2400,d42bad48) at fork_exit+0x7a
    fork_trampoline() at fork_trampoline+0x8
    --- trap 0x1, eip = 0, esp = 0xd42bad7c, ebp = 0 ---
    db> reset

Me being a n00b, I have no idea what's going on.  But I /do/ know that I can
reliably produce a panic while ripping this CD.

  - Damian