ZFS passdevgonecb

[Da Rock]

I hate jumping in like this out of the blue, but time is not on my side 
atm with a lot going on.

I have a problem with some devices disappearing on various versions of 
FreeBSD and machines (laptops, workstations/servers). Umass are the 
norm, with the message occurring most on usb sticks and sd cards.

Big problem atm is that my file server has a failed disk in the raid, 
and I've tried replacing it with a new drive (twice now), and both times 
it begins to resilver and then it is "REMOVED". If I online it again, it 
goes for about 10mins then REMOVED again.

Dmesg shows that the device is removed from the devfs with a 
passdevgonecb/lost device message. This apparently occurs right at boot 
too, as it shows amongst the usual scrolling during boot.

I had a chat with someone and they mentioned the cable and/or controller 
could be the issue. Could anyone add any insight or tests I could do? 
I'm not exactly claim to be an expert at zfs, so maybe something might 
need addressing there too.

I'd particularly appreciate a means of testing the controller.

ATM the main theory is to replace the board - not a happy thought! :/

TIA