Messages in this thread |  | | | Date | Tue, 5 Oct 1999 18:19:30 -0400 | | From | Johannes Erdfelt <> | | Subject | Re: [linux-usb] Re: USB device allocation |
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On Wed, Oct 06, 1999, Patrick Schaaf <phbof@bof.de> wrote: > AHEM. Does linux-kernel really need another round of devfs vs. /dev discussion?
Not really. Here's the issue for those people who don't know:
As it stands right now, there is no solution for naming of Plug and Play devices. I'm specifically interested in USB since that's what I work on, but this applies to everything plug and play (even PCMCIA)
The problem is if you have 2 mice, how do you name? What if they are plugged in a different order, now 1 becomes 2 and 2 becomes 1.
How do you differentiate between the 2? This can be difficult in USB since in some cases, 2 different mice look identical to the software. The only way you can differentiate is based on topology, exactly where it's plugged into the bus (which port on which hub).
This is a problem that hasn't been solved yet.
There's other problems like you can theoretically have 500 USB mice connected to a PC (over multiple USB busses). There wouldn't be enough device nodes for that. It's a possibility, an unlikely possibility, but I could see someone plugging in a ton of one device into a computer for some reason.
Of course many busses have similar problems as USB has for number of devivces connected (multiple Wide SCSI cards maxxed out with Hard Drives can run out of device nodes now).
The big problem people haven't run into yet and haven't solved is the device naming issue.
JE
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