loader.conf ignores setting variable ending in _type

Hi,

I maintain the mxge (10GbE) driver.  A user complained to me
that one of my driver's tunables was ignored when he set it
in /boot/loader.conf.   I reproduced his problem both on -current
and 7.2.  I think there may be some quirk which is causing the
loader to ignore this variable, but my 4th skills are non-existent,
and I'm looking for some help.

To reproduce this bug, I used a loader.conf which
looks like this:

console=comconsole
if_mxge_load="YES"
mxge_eth_z8e_load="YES"
mxge_rss_eth_z8e_load="YES"
hw.mxge.rss_hash_type="2"
hw.mxge.max_slices="2"



After interrupting the boot, I could confirm that rss_hash_type
was not set:

..................................................................
Hit [Enter] to boot immediately, or any other key for command prompt.
Booting [/boot/kernel/kernel] in 8 seconds...

Type '?' for a list of commands, 'help' for more detailed help.
OK show hw.mxge.max_slices
2
OK show hw.mxge.rss_hash_type
variable 'hw.mxge.rss_hash_type' not found
...................................................................

I have no problem setting hw.mxge.rss_hash_type while the machine is
up via kenv.  Also, it seems to stick when set manually from the
loader.


After poking around for quite a while, I noticed that the loader
refuses to honor any variable ending in _type loaded from
loader.conf.

Is this because the suffix "_type" (for module_type) is somehow
reserved and I should not be using a tunable ending in _type
Or is this a bug in the loader?

Thanks,

Drew