Thanks.Do you mean that if "07 25 01 81 02 00 00" (Unrecognized) was moved after the "Endpoint Descriptor", then the driver should recognize it as some AudioControl Endpoint Descriptor (as described in Table 4-21: Class-Specific AS Isochronous Audio Data Endpoint Descripton in http://www.usb.org/developers/devclass_docs/audio10.pdf)? I have no idea if this is an easy modification (it does not sound complex to me, but I never wrote firmware for USB audio devices!)
- Yves On 22/04/2013 21:23, Torstein Hegge wrote:
On Mon, Apr 22, 2013 at 20:44:40 +0200, Daniel Mack wrote:Also, the lsusb dumps don't contain a audio specific header descriptor, which normally looks like this: AudioControl Endpoint Descriptor: bLength 7 bDescriptorType 37 bDescriptorSubtype 1 (EP_GENERAL) bmAttributes 0x01 Sampling Frequency bLockDelayUnits 0 Undefined wLockDelay 0 Undefined And without the "Sampling Frequency" bit in bmAttributes, the driver will bail out early (clock.c):I think it has the class specific endpoint descriptor, but it is in front of the standard endpoint descriptor. From the 'lsusb -v': AudioStreaming Interface Descriptor: bLength 14 bDescriptorType 36 bDescriptorSubtype 2 (FORMAT_TYPE) bFormatType 1 (FORMAT_TYPE_I) bNrChannels 2 bSubframeSize 2 bBitResolution 16 bSamFreqType 2 Discrete tSamFreq[ 0] 16000 tSamFreq[ 1] 48000 ** UNRECOGNIZED: 07 25 01 81 02 00 00 Endpoint Descriptor: bLength 9 bDescriptorType 5 bEndpointAddress 0x03 EP 3 OUT bmAttributes 1 Transfer Type Isochronous Synch Type None Usage Type Data wMaxPacketSize 0x00c0 1x 192 bytes bInterval 1 bRefresh 0 bSynchAddress 0 The UNRECOGNIZED bit matches the missing AudioControl endpoint descriptor. Even if this is against the specification, devices that does this is out there. I have seen the same thing on a Sennheiser BTD-500, but that only supports one frequency, so I didn't hit this problem. Torstein
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