SiI3112a possible workaround?

I was searching the net today and I came across this little gem in a 
Linux mailing list:

http://www.uwsg.iu.edu/hypermail/linux/kernel/0307.3/1349.html

Notably:

1) As some others suggested on the list, the problem with very slow
transfer and timeouts if you try to enable DMA, can be fixed by the
following lines in an appropriate rc file:

  hdparm -X66 -d1 /dev/hda
  echo "max_kb_per_request:15" > /proc/ide/hdX/settings
  (repeat for both drives, e.g. hde and hdg).

As I have one of these unfortunate controllers, I was wondering if it is 
possible to do something like this in FreeBSD?  sysctl doesn't seem to 
have anything and I'm not sure what to look for in the sources.  Does 
FreeBSD have any sort of analog to the above hdparm command?