Date: Wed, 11 Aug 1999 16:03:32 +0200 (MET DST) From: Nick Hibma <nick.hibma@jrc.it> To: Zhihui Zhang <zzhang@cs.binghamton.edu> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Questions on new-bus source code Message-ID: <Pine.GSO.3.95q.990811153015.22053K-100000@elect8> In-Reply-To: <Pine.GSO.3.96.990806144109.24194A-100000@sol.cs.binghamton.edu>
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> (2) I guess that the probe process of all devices on the tree is triggered > by root_bus_configure() in subr_bus.c. It is done from top to bottom, > i.e. the probe process should be propagated down the device tree from > root_bus. Am I right? How does this tree structure achieve the dynamic > feature of device configuring (adding/removing devices on the fly)? When the loaded module registers itself as a driver in a devclass, all the non-attached devices are probed by calling the method BUS_DRIVER_ADDED (in devclass_add_driver). Devices that are already attached are not detached forcefully. There is still some discussion going on on whether a driver needs to give up a device when a better fitting driver is loaded (a stub versus a full blown driver for a device). See also the listed methods for busses (sys/kern/bus_if.m) and for devices (sys/kern/device_if.m). Nick -- ISIS/STA, T.P.270, Joint Research Centre, 21020 Ispra, Italy To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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