Date: Sun, 21 Mar 2004 19:13:49 -0800 From: Wes Peters <wes@softweyr.com> To: "M. Warner Losh" <imp@bsdimp.com>, ticso@cicely.de, ticso@cicely12.cicely.de Cc: arch@freebsd.org Subject: Re: Opinions about using USB serial numbers Message-ID: <200403211913.49901.wes@softweyr.com> In-Reply-To: <20040320.184336.88475380.imp@bsdimp.com> References: <20040320052007.GC33602@cicely12.cicely.de> <20040320.184336.88475380.imp@bsdimp.com>
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On Saturday 20 March 2004 17:43, M. Warner Losh wrote: > In message: <20040320052007.GC33602@cicely12.cicely.de> > > Bernd Walter <ticso@cicely12.cicely.de> writes: > : I have a lot to do with systems using many USB devices of the same > : kind. > : Currently device are named acording to their probing order. > : That result in the problematic that device names can change after > : reboot or replugging in different order. > : > : I would like to add functionality for creating alias devnodes > : including the serial numbers (if the device has one setup). > : E.g. for a ucom(4) device you will get /dev/ucom0 and > : ucom.serialnumber. If the device has no serial numer there will be > : just /dev/ucom0 as befor. > : > : Another solution could be to create the nodes in a tree form: > : /dev/usbchannel0/hubport1/pubport2/ucom > : That would work for devices without serial numbers too, but I > : personally dislike this way. > > I'd rather that we have a generic binding of a device instance number > to a pnp location. > > However, having said that, you can use devd to extract the information > from the node and then create a symbolic link... Using the serial number would give the ability to reliably connect to a specific device, or to know that it is not currently present in the system. For certain embedded applications, that could be very nice. -- "Where am I, and what am I doing in this handbasket?" Wes Peters Softweyr LLC wes@softweyr.com http://softweyr.com/
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