reset with fwcontrol -R

[Kazumaro Aoki]

I have several experiences that sudden reboot is happened just after
"fwcontrol -R foo.dv" was invoked.  The operating system is FreeBSD
7.2R/i386.  Before I use 7.2R, I used 6.3R and I never experienced
such phenomenon.

The sudden reboot is not always occurred.  The probability is less than
1/200, when I randomly used "fwcontrol -R".  However, there seems to
exist the condition that the probability is considerably high.

I used the PC as a video recorder with two firewire bus, and each bus
connects to video capture box (in total two capture box).  I record
several programs at Sunday morning, and I met a sudden reboot at
8:30am with probability higher than 1/2.

The recording schedule is as follows.
06:30:00.00 - 06:28:11 fwcontrol -u 0 -R
07:00:00.07 - 07:26:26 fwcontrol -u 0 -R
07:00:45.00 - 07:28:16 fwcontrol -u 1 -R
08:00:00.00 - 08:29:58 fwcontrol -u 0 -R
08:29:59.93 - 08:57:26 fwcontrol -u 0 -R
08:30:00.08 - 08:58:46 fwcontrol -u 1 -R
The one of the two last fwcontrol seems to cause a reboot.

I tried the following procedure several times.
[offset] [duration] [command]
00:00:00 - 58 sec fwcontrol -u 1 -R
00:01:00 - 58 sec fwcontrol -u 0 -R
00:02:00 - 58 sec fwcontrol -u 0 -R
00:02:00 - 58 sec fwcontrol -u 1 -R
I only met one reboot.

I wander how to identify the reason.  Do you have any suggestion to
find (and fix) the reason (or problem)?

Best regards,

Kazumaro Aoki