Tim Roberts <timr@xxxxxxxxx> wrote: wade wrote: Hi Tim. Not pretty but here it is: This is helpful. Your MIDI descriptors are virtually identical to the ones in appendix B of the spec. And when you plug this in and start a MIDI program, you see bulk transfers happening? With MidiOx open, the host is issuing INs once every ~9uS ;CS_MIDI_DESC_START ;*** Class Specific MS Interface Header Desriptor db 007h ;bLength db 024h ;bDescriptorType (CS_INTERFACE) db 001h ;bDescriptorSubtype db 000h ;bcdMSC db 001h ;bcdMSC db 63 ; Size-LSB db 0 ; Size - MSB How did you get 63 for the size? Shouldn't it be 7+6+6+8+8 = 35? I was having problems early on getting XP to recognize the MIDI portion of the device so I made our MIDI descriptors violate 18.104.22.168 just like the example. Turns out the issue was related to not handling audio feature unit requets correctly. I never changed them back. I just changedit back and Vista and XP seem to be fine with it. IBy the way, I'm convinced the USB MIDI spec has a mistake in this descriptor in the sample. They show 0x0041 for the size in section B.4.2, but based on the description in 22.214.171.124, it should be 7+6+6+9+9 = 0x0025. To get 0x0041, you have to include the endpoint descriptors, and that doesn't meet 126.96.36.199. However, apparently no one checks this. Aparently not! ;*** MIDI Out Jack Descriptor - MIDIJACK(OUT,EMB,2)->IN(ID2/PIN1) --> To USB db 008h ;bLength db 024h ;bDescriptorType db 003h ;bDescriptorSubtype (MIDI_OUT_JACK) db 001h ;bJackType (EMBEDDED) db 003h ;bJackId db 001h ;bNrInputPins db 002h ;baSourceID(1) db 001h ;baSourcePin(1) ;*** MIDI Out Jack Descriptor - MIDIJACK(OUT,EXT,4)->IN(ID1/PIN1) db 008h ;bLength db 024h ;bDescriptorType db 003h ;bDescriptorSubtype (MIDI_OUT_JACK) db 002h ;bJackType (EXTERNAL) db 004h ;bJackId db 001h ;bNrInputPins db 001h ;baSourceID(1) db 001h ;baSourcePin(1) The spec shows these as being 9 bytes long, with a string descriptor ordinal at the end. If this works for you in XP, then I guess usbaudio.sys must not care. Oops. -- Tim Roberts, timr@xxxxxxxxx Providenza & Boekelheide, Inc. --------------------------------- Tonight's top picks. What will you watch tonight? Preview the hottest shows on Yahoo! TV.