Date: Sun, 21 Mar 2004 08:11:01 +0100 From: Bernd Walter <ticso@cicely12.cicely.de> To: "M. Warner Losh" <imp@bsdimp.com> Cc: ticso@cicely.de Subject: Re: Opinions about using USB serial numbers Message-ID: <20040321071100.GH33602@cicely12.cicely.de> 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 Sat, Mar 20, 2004 at 06:43:36PM -0700, 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. Currently we have non really working - even cam binding is evil because it's a boot time only. > However, having said that, you can use devd to extract the information > from the node and then create a symbolic link... OK - lets try it with devd. Usefull devd support is required anyway. That's what I get on plugging in a device: Processing event '? at on uhub2' Pushing table Processing nomatch event Popping table Processing event '+ubser0 at on uhub2' Pushing table device-name=ubser0 Processing attach event I think the '?' one is because no driver attaches at device level. ubser is an interface level driver as most USB ones. What I need is the following for devices: vendor-id, device-id, device-class, device-protocoll, vendor-string, device-string, serial-id. At interface level additionally: interface-class, interface-subclass, interface-protocoll, interface-string. I've seen some places where bus_child_pnpinfo_str() and bus_child_location_str() was used for extended informations. Is this all I have to implement? Can I put the above data in it or are there any restrictions? It seems that dv_pnpinfo[128] could be to small for all of them. We can discuss if strings are required, but also USB serial number is a (unicode)string and strings can be 254 bytes long. What about whitespace in strings? Does usbd still serve any usefull purpose after having the above data via devctl? -- B.Walter BWCT http://www.bwct.de ticso@bwct.de info@bwct.de
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