silly nit: today's date and only one comma :)

using the new PCI_PNP_INFO macros would let this be autoloaded by devmatch

BUS_PROBE_GENERIC-1 might be better here...

style nit

seems like a kassert sort of situation

default: panic() ?

For maintainability, I suggest using a lookup-table a la struct bge_type in sys/dev/bge/if_bge.c; that would allow for trivially adding additional devids. vmd_probe() would then just walk the table looking for a match.

In addition, the table could also be passed to MODULE_PNP_INFO() for automatic loading of the kernel module.

Please don't use a magic number; either use one of the existing BUS_PROBE_* defines, or add a new one and use it here.

Since this is a wrapper around bus_space_write_X(), and that takes the value to write as the last argument, shouldn't vmd_write_config() also take the value to write as the last argument?

Similarly, this should also have it's last two args reversed.

You have a bunch of duplicates here...?

I'll fix the comma. The date is a moving target ...

Do you have a good example for me to copy?

Should I add

KASSERT(1, ("Invalid width requested"));

infront of the return.

You need to make a line break after a sentence stop.

Ran igor and mandoc -Tlint. It flags the wrong date.