Date: Mon, 23 May 2011 10:32:19 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-hackers@freebsd.org, philip-freebsd1@soeberg.net Cc: jfv@gmail.com Subject: Re: device_detach() on a device used by ixgbe driver (FreeBSD 7-STABLE through to 9-CURRENT) Message-ID: <201105231032.20084.jhb@freebsd.org> In-Reply-To: <4DDA6B95.3090704@soeberg.net> References: <4DDA6B95.3090704@soeberg.net>
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On Monday, May 23, 2011 10:13:41 am Philip Soeberg wrote: > 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".. Yes, that is true. > 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) device_if.m was probably just never updated from when BUS_PROBE_* were added. Updating it would be a good thing. > 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.. That is not universally supported (i.e. it's not a part of new-bus specifically). For buses that support hinted devices, they do all generally support being able to disable a hinted device, but disabling bus-enumerated devices is not generally supported. > 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? I think ixgbe has to be fixed to use BUS_PROBE_DEFAULT. Very few drivers should use '0' for their probe return value. -- John Baldwin
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