From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <200301152200.h0FM0Fw21426@augusta.math.psu.edu> To: 9fans@cse.psu.edu Subject: Re: [9fans] USB weirdness. In-Reply-To: Your message of "Wed, 15 Jan 2003 21:33:45 GMT." From: Dan Cross Date: Wed, 15 Jan 2003 17:00:15 -0500 Topicbox-Message-UUID: 42288e60-eacb-11e9-9e20-41e7f4b1d025 > No, that's quite likely. If the device class of the device descriptor > is set to 0, so will be the subclass, and most likely the protocol. It > indicates that the real information is within the configuration. > > As it says in Table 9-7 of USB 1,1: > > If this field is reset to zero, each interface > within a configuration specifies its own > class information and the various > interfaces operate independently. > > Configurations represent different operating modes of a device; this > is often used to have a device which has behaviour according to the > standard, and a proprietary mode as well. Quite a lot of proprietary > devices pass the buck to the configuration descriptor. Okay, that makes sense, I guess. > Unfortunately, the Plan 9 arrangements don't express alternate > configurations. Bummer. So does this mean I'll have to open every device that's ``Enabled 0x000000'' and probe the configuration to find the device I'm looking for? Hmm.... Okay. - Dan C.