[PATCH] Fix for USB ugen panics
jay at evilrealms.net
Thu Jan 8 18:17:14 PST 2004
> or from a sourceforge-project:
> In section 7.5.3 "Bandwidth Management" it says something about
> "Set Configuration" request and the zero-setting. Maybe I
> misunderstood the paragraph.
"...by providing a zero-bandwidth interface (alternate setting zero) and 16
alternate settings interfaces wth 8Mbps down to 0.5Mbps bandwidth in
descending 0.5Mbps steps."
These can be accessed through USB_SET_ALTINTERFACE with a value from 0 to 16.
"The default alternate setting zero (with zero bandwidth) selected by a Set
I think this is the badly phrased sentence in question. What the author is
trying to say is that alternate interface 0 will be selected by default upon
USB_SET_CONFIGURATION - which seems a bit daft without explaining which
configurations are available. Try a USB_SET_CONFIGURATION of 1, and see if the
16 interfaces are available then.
> Perhaps you can tell me a second thing. In section 7.5.2 they say
> there are 0-length packets used for frame-sync. I have never seen
> a 0-length packet coming from the interface, but some packets are
> (irregulary) shorter. Is the FreeBSD ugen-driver supporting 0-length
Now that, I'm not sure of. :)
But if their device does that, which is USB 1.1 compliant, it's probably in
the spec and so probably supported by ugen. Probably, there's only one real
way to find out. ;)
http://www.evilrealms.net/ - Systems Administrator & Developer
http://www.imperial.ac.uk/ - 3rd year CS student
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