cable detection

I have a junky machine with a UDMA-33 cable between a UDMA-66
controller and drives.   Using a year old -current, the ATA driver 
complains that the cables aren't capable of UDMA66 operation, and
throttles things back to UDMA33.

Using -current from ~1 week ago,  this no longer happens and I get:

atapci0: <Intel ICH UDMA66 controller> port 0xffa0-0xffaf at device 31.1 on pci0
ata0: at 0x1f0 irq 14 on atapci0
ata0: [MPSAFE]
ata1: at 0x170 irq 15 on atapci0
ata1: [MPSAFE]
<...>
GEOM: create disk ad0 dp=0xc20bc160
ad0: 9779MB <IBM-DPTA-371020> [19870/16/63] at ata0-master UDMA66
acd0: CDROM <ATAPI-CD ROM-DRIVE-56MAX> at ata1-master PIO4
SMP: AP CPU #1 Launched!
ad0: WARNING - READ_DMA UDMA ICRC error (retrying request)
ad0: WARNING - READ_DMA UDMA ICRC error (retrying request)
ad0: FAILURE - READ_DMA status=51<READY,DSC,ERROR>
error=84<ICRC,ABORTED>
ad0: WARNING - READ_DMA UDMA ICRC error (retrying request)
ad0: WARNING - READ_DMA UDMA ICRC error (retrying request)
ad0: FAILURE - READ_DMA status=51<READY,DSC,ERROR>
error=84<ICRC,ABORTED>
Mounting root from ufs:/dev/ad0s1a
setrootbyname failed
ffs_mountroot: can't find rootvp
Root mount failed: 6

Manual root filesystem specification:
  <fstype>:<device>  Mount <device> using filesystem <fstype>
                       eg. ufs:da0s1a
  ?                  List valid disk boot devices
  <empty line>       Abort manual input

mountroot> 


I realize that this is not a whole lot to go on, but it seems to be
wedged here, and the machine is 3000 miles away, so a verbose boot
will have to wait for people to arrive at the office in CA.

I was just wondering if this was a known issue,  or if there was a way
to make things gracefully fall back to UDMA33 (aside from disabling
DMA at in the loader, and then using atacontrol to enable it after boot)


Drew