Testing CAM wrapper for ata(4) controller drivers

i've stumbled over a problem with ATA_CAM. when i accessing my dvd-drive i'm
not able to access any other cam members (ada* e.g.).

when i issue the following command:

`cdrecord dev=2,1,0 blank=all'

binaries such as ls, top or vmstat simply stall until cdrecord finishes.

this is the output of `camcontrol devlist -v':

scbus0 on ahcich0 bus 0:
<>                                 at scbus0 target -1 lun -1 ()
scbus1 on ahcich1 bus 0:
<>                                 at scbus1 target -1 lun -1 ()
scbus2 on ata2 bus 0:
<HDS722516VLAT80 V34OA63A>         at scbus2 target 0 lun 0 (ada0,pass0)
<HL-DT-ST DVDRAM GSA-H10N JL12>    at scbus2 target 1 lun 0 (pass1,cd0)
<>                                 at scbus2 target -1 lun -1 ()
scbus3 on ahcich2 bus 0:
<SAMSUNG SP2504C VT100-50>         at scbus3 target 0 lun 0 (ada1,pass2)
<>                                 at scbus3 target -1 lun -1 ()
scbus4 on ahcich3 bus 0:
<>                                 at scbus4 target -1 lun -1 ()
scbus5 on ahcich4 bus 0:
<>                                 at scbus5 target -1 lun -1 ()
scbus6 on ahcich5 bus 0:
<>                                 at scbus6 target -1 lun -1 ()
scbus7 on ahcich6 bus 0:
<>                                 at scbus7 target -1 lun -1 ()
scbus8 on ahcich7 bus 0:
<>                                 at scbus8 target -1 lun -1 ()
scbus-1 on xpt0 bus 0:
<>                                 at scbus-1 target -1 lun -1 (xpt0)

i'm running r200176 (amd64).

cheers.
alex