ATA cdrom boot wierdness?

[Julian Elischer]

My test system  (todays sources via p4) has started doing:
...
atapci0: <Intel ICH2 UDMA100 controller> port 
0xffa0-0xffaf,0x376,0x170-0x177,0x3f6,0x1f0-0x1f7 at device 31.1 on pci0
ata0: channel #0 on atapci0
ata1: channel #1 on atapci0
...
ad0: 9541MB <ST310211A/3.39> [19386/16/63] at ata0-master UDMA100
ATAPI_RESET time = 50us
ATAPI_RESET time = 50us
acd0: FAILURE - MODE_SENSE_BIG timed out
ATAPI_RESET time = 50us
acd0: FAILURE - MODE_SENSE_BIG timed out
ATAPI_RESET time = 50us
acd0: FAILURE - MODE_SENSE_BIG timed out
ATAPI_RESET time = 50us
acd0: FAILURE - MODE_SENSE_BIG timed out
ATAPI_RESET time = 50us
acd0: FAILURE - MODE_SENSE_BIG timed out
acd0: CDROM <CDU5211/YYS2> at ata1-master PIO4
ATAPI_RESET time = 50us
acd0: FAILURE - TEST_UNIT_READY timed out
ATAPI_RESET time = 50us
acd0: FAILURE - PREVENT_ALLOW timed out
ATAPI_RESET time = 50us
acd0: FAILURE - TEST_UNIT_READY timed out
ATAPI_RESET time = 50us
acd0: FAILURE - TEST_UNIT_READY timed out
ATAPI_RESET time = 50us
acd0: FAILURE - PREVENT_ALLOW timed out
ATAPI_RESET time = 50us
acd0: FAILURE - TEST_UNIT_READY timed out
ATAPI_RESET time = 50us
acd0: FAILURE - PREVENT_ALLOW timed out
ATAPI_RESET time = 50us
acd0: FAILURE - TEST_UNIT_READY timed out
ATAPI_RESET time = 50us
acd0: FAILURE - TEST_UNIT_READY timed out
ATAPI_RESET time = 50us
acd0: FAILURE - PREVENT_ALLOW timed out
ATAPI_RESET time = 50us
acd0: FAILURE - TEST_UNIT_READY timed out
ATAPI_RESET time = 50us
acd0: FAILURE - PREVENT_ALLOW timed out
ATAPI_RESET time = 50us
acd0: FAILURE - TEST_UNIT_READY timed out
ATAPI_RESET time = 50us
acd0: FAILURE - TEST_UNIT_READY timed out
ATAPI_RESET time = 50us
acd0: FAILURE - PREVENT_ALLOW timed out

Each of these messages takes between 4 and 30 seconds to print out
so booting is considerably slowed.

any suggestions/ideas?