boot hang with tag=RELENG_5_2

[Elliot Finley]

this is with tag=RELENG_5_2 as of Feb. 8

I have a CD burner as my primary slave.  It shows up in dmesg like:

acd0: CDRW <LITE-ON LTR-52246S> at ata0-slave PIO4

booting hangs with:

ata0-slave : TIMEOUT - SETFEATURES SET TRANSFER MODE retrying (0 retries
left)
ata0-slave : TIMEOUT - SETFEATURES SET TRANSFER MODE retrying (0 retries
left)

but if I have a CD in the drive it boots just fine.  No
errors/warnings/freezes.

Elliot