Attaching ugen to all usb devices
M. Warner Losh
imp at bsdimp.com
Mon Dec 25 12:40:21 PST 2006
In message: <200612251456.42770.amistry at am-productions.biz>
Anish Mistry <amistry at am-productions.biz> writes:
: Many usb devices can be attached as different devices along with
: being functional with some libusb app that requires ugen.
: eg. HP PSC Printers will attach as ulpt, if ulpt isn't loaded umass
: can attach to access the card slot, if neither of these are loaded
: ugen will attach which is required to run the hplip vendor software
: so that the printer, scanner, and fax machine can be accessed.
You should review how the device presents itself to the system. If
both umass and ulpt attach to it, it should be possible to make them
both attach at the same time.
As for ugen, one could easily hack uhub to allow this kind of access.
ugen really shouldn't be attaching to any device at all, but instead
the usb bus (aka uhub) should allow ugen-like acess to each of the
: It would be very helpful to allow ulpt, umass, and ugen to all attach
: to the device. This would allow full functionality. Simultaneous
: access isn't necessary, but might be nice in the future.
That would be a nightmare. Trust me. I've looked into it in the past
it was scary.
: The closest thing I can think of that allows similar behavior is
: vgapci that allow acpi_video and a drm driver to both access the
: video card.
Well, it doesn't really. newbus has a very strong notion of each node
in the tree has one and only one (or zero) devices attached.
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