device_detach() on a device used by ixgbe driver (FreeBSD 7-STABLE through to 9-CURRENT)

[Philip Soeberg]

Hi fellow FreeBSD hackers,

I've just completed designing a new driver for the Intels IXGBE suite of 
network adapters, but is building my driver as a kernel module to be 
loaded after system boot.

The current sys/dev/ixgbe/ixgbe.c driver which attach to Intels adapters 
return a zero in it's probe() function (which equals to 
BUS_PROBE_SPECIFIC).. This has the distinct disadvantage that I cannot, 
through my module, call a device_detach() on the devices I support, and 
afterward expect being probed for them. A BUS_PROBE_SPECIFIC, according 
to wording in sys/sys/bus.h, inform the OS that "Only I can use this 
device".

I assume this (transcanding from FreeBSD 7.0-STABLE through to FreeBSD 
9-CURRENT) is in error? I would expect sys/dev/ixgbe/ixgbe.c's probe() 
function to return BUS_PROBE_DEFAULT, which is the "Base OS default 
driver"..

If this is true, then we should probably also update 
sys/kern/device_if.m's description of the probe() method as to reflect 
the BUS_PROBE_* return values in a clearer way than is currently described.
Do you want me to provide a patch? (it's really a one liner for ixgbe.c 
and a couple of alterations to the device_if.m, if need be)

I would also expect the ixgbe.c driver to do a quick resource_disabled() 
in it's attach() function, so that we can disable specific adapters 
through kenv hint.ix.0.disabled=1..

Given that I can't use device_detach() on a device hogged by the IXGBE 
driver, can any one of you help me with a way around this problem? I 
can't use the hints, and I can't detach() the device.. how can I get my 
kernel module to attach the device?

Thanks,
Phil