Date: Tue, 17 Oct 2000 00:53:15 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: gcorcoran@lucent.com (Gary T. Corcoran) Cc: freebsd-hackers@FreeBSD.ORG, freebsd-net@FreeBSD.ORG Subject: Re: Module parameters? (WildWire DSL card driver) Message-ID: <200010170053.RAA04059@usr05.primenet.com> In-Reply-To: <39E7AB10.EADBB53B@lucent.com> from "Gary T. Corcoran" at Oct 13, 2000 08:38:40 PM
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> Back in July I was asking about the capability to set parameters (variables) > when loading my DSL driver module. There was a small flurry of activity > about some initial ideas on how to do it, but I never heard any more about > it. Did you (Mike, Warner, or anybody) have time to work on it? Did this > capability get put into release 4.1, by any chance? :) A common trick "in the old days" was to load a parameter module that the driver module depended up, and give it a hook that it could call to get data from the parameter module, by reference to a statis structure. You would send the data down to the parameter module before you load the driver module; thus: 1) Load paramter module 2) Open parameter module psuedo device 3) Ioctl parameters up/down via the pseudo device 4) Load the deriver module 5) Driver module attach routine call parameter_fetch() routine out of parameter module 6) Parameter module returns static parameter structure, by reference 7) Driver dereferences parameters out of static struct 8) Driver completes attach Really, it seems to me that if this driver looks like an ethernet interface, you should be able to set the parameters after the atttach, before bringing the interface up. Alternately, if the problem is lack of reference counting on FreeBSD's part, and you therefore can't do the job on the open, since you can't track closes aws they happen, only the last clse, there are a couple of approaches: A) Have one driver, but two devices; one for control, and one for data B) Have only one device, but inactivate it until a special ioctl() starting it up is issued; thus: 1) Open 2) Set parameters 3) ioctl(fd,LUCENT_START,...) 4) ... 5) ioctl(fd,LUCENT_STOP,...) 6) Set new parameters 7) ioctl(fd,LUCENT_START,...) 8) ... One of these aprroaches should be able to work for you; the parameter driver approach with a pseudo device will definitely work, but is much less elegant (parameters on an attach probably mean that you are doing something in an attach that really belongs elsewhere). Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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