dram🎀UPDATE: Confirmed! It's real! See ayumi's lsusb dump: https://transfem.social/notes/a9j1rc059tdj0vpx
Today in vendors slipping single bits (or single bit!) of information into weird places:
I am *completely* certain that Google once made a USB-C audio adapter that has a *different USB PID* depending on whether it has something plugged into it.
I am somewhat certain that it's 18d1:5025 with something plugged in, and 18d1:5029 without.
@ayumi
@dramforever@mastodon.social I have this one. When it’s not connected to anything `lsusb` output looks like this: ``` Bus 003 Device 005: ID 18d1:5029 Google Inc. USB-C to 3.5mm-Headphone Adapter Negotiated speed: Full Speed (12Mbps) Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 1.10 bDeviceClass 0 [unknown] bDeviceSubClass 0 [unknown] bDeviceProtocol 0 bMaxPacketSize0 64 idVendor 0x18d1 Google Inc. idProduct 0x5029 USB-C to 3.5mm-Headphone Adapter bcdDevice 23.20 iManufacturer 3 Google iProduct 1 USB-C to 3.5mm-Headphone Adapter iSerial 2 [redacted] bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 0x0022 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0xa0 (Bus Powered) Remote Wakeup MaxPower 100mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 1 bInterfaceClass 3 Human Interface Device bInterfaceSubClass 0 [unknown] bInterfaceProtocol 0 iInterface 0 HID Device Descriptor: bLength 9 bDescriptorType 33 bcdHID 1.11 bCountryCode 0 Not supported bNumDescriptors 1 bDescriptorType 34 (null) wDescriptorLength 35 Report Descriptors: ** UNAVAILABLE ** Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x88 EP 8 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0010 1x 16 bytes bInterval 8 can't get debug descriptor: Resource temporarily unavailable Device Status: 0x0000 (Bus Powered) ``` and when it’s connected to headphones (without a microphone, the output for a headphones with a microphone looks different, though PID is the same) it looks like this: ``` Bus 003 Device 006: ID 18d1:5025 Google Inc. USB-C to 3.5mm-Headphone Adapter Negotiated speed: Full Speed (12Mbps) Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 1.10 bDeviceClass 0 [unknown] bDeviceSubClass 0 [unknown] bDeviceProtocol 0 bMaxPacketSize0 64 idVendor 0x18d1 Google Inc. idProduct 0x5025 USB-C to 3.5mm-Headphone Adapter bcdDevice 23.20 iManufacturer 3 Google iProduct 1 USB-C to 3.5mm-Headphone Adapter iSerial 2 [redacted] bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 0x00a2 bNumInterfaces 3 bConfigurationValue 1 iConfiguration 4 USB-C to 3.5mm-Headphone Adapter bmAttributes 0xa0 (Bus Powered) Remote Wakeup MaxPower 100mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 1 bInterfaceClass 1 Audio bInterfaceSubClass 1 Control Device bInterfaceProtocol 0 iInterface 5 USB-C to 3.5mm-Headphone Adapter AudioControl Interface Descriptor: bLength 9 bDescriptorType 36 bDescriptorSubtype 1 (HEADER) bcdADC 1.00 wTotalLength 0x003a bInCollection 1 baInterfaceNr(0) 1 AudioControl Interface Descriptor: bLength 12 bDescriptorType 36 bDescriptorSubtype 2 (INPUT_TERMINAL) bTerminalID 14 wTerminalType 0x0101 USB Streaming bAssocTerminal 0 bNrChannels 2 wChannelConfig 0x0003 Left Front (L) Right Front (R) iChannelNames 0 iTerminal 21 Headphone AudioControl Interface Descriptor: bLength 9 bDescriptorType 36 bDescriptorSubtype 3 (OUTPUT_TERMINAL) bTerminalID 15 wTerminalType 0x0302 Headphones bAssocTerminal 14 bSourceID 4 iTerminal 0 AudioControl Interface Descriptor: bLength 13 bDescriptorType 36 bDescriptorSubtype 6 (FEATURE_UNIT) bUnitID 16 bSourceID 14 bControlSize 2 bmaControls(0) 0x0001 Mute Control bmaControls(1) 0x0002 Volume Control bmaControls(2) 0x0002 Volume Control iFeature 0 AudioControl Interface Descriptor: bLength 15 bDescriptorType 36 bDescriptorSubtype 8 (EXTENSION_UNIT) bUnitID 4 wExtensionCode 0x0bda bNrInPins 1 baSourceID(0) 16 bNrChannels 2 wChannelConfig 0x0003 Left Front (L) Right Front (R) iChannelNames 0 bControlSize 1 bmControls(0) 0x01 iExtension 0 Endpoint Descriptor: bLength 9 bDescriptorType 5 bEndpointAddress 0x87 EP 7 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0010 1x 16 bytes bInterval 8 bRefresh 0 bSynchAddress 0 Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 1 bAlternateSetting 0 bNumEndpoints 0 bInterfaceClass 1 Audio bInterfaceSubClass 2 Streaming bInterfaceProtocol 0 iInterface 21 Headphone Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 1 bAlternateSetting 1 bNumEndpoints 1 bInterfaceClass 1 Audio bInterfaceSubClass 2 Streaming bInterfaceProtocol 0 iInterface 0 AudioStreaming Interface Descriptor: bLength 7 bDescriptorType 36 bDescriptorSubtype 1 (AS_GENERAL) bTerminalLink 14 bDelay 1 frames wFormatTag 0x0001 PCM AudioStreaming Interface Descriptor: bLength 11 bDescriptorType 36 bDescriptorSubtype 2 (FORMAT_TYPE) bFormatType 1 (FORMAT_TYPE_I) bNrChannels 2 bSubframeSize 3 bBitResolution 24 bSamFreqType 1 Discrete tSamFreq[ 0] 48000 Endpoint Descriptor: bLength 9 bDescriptorType 5 bEndpointAddress 0x04 EP 4 OUT bmAttributes 9 Transfer Type Isochronous Synch Type Adaptive Usage Type Data wMaxPacketSize 0x0174 1x 372 bytes bInterval 1 bRefresh 0 bSynchAddress 0 AudioStreaming Endpoint Descriptor: bLength 7 bDescriptorType 37 bDescriptorSubtype 1 (EP_GENERAL) bmAttributes 0x01 Sampling Frequency bLockDelayUnits 0 Undefined wLockDelay 0x0000 Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 2 bAlternateSetting 0 bNumEndpoints 1 bInterfaceClass 3 Human Interface Device bInterfaceSubClass 0 [unknown] bInterfaceProtocol 0 iInterface 0 HID Device Descriptor: bLength 9 bDescriptorType 33 bcdHID 1.11 bCountryCode 0 Not supported bNumDescriptors 1 bDescriptorType 34 (null) wDescriptorLength 35 Report Descriptors: ** UNAVAILABLE ** Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x88 EP 8 IN bmAttributes 3 Transfer Type Interrupt Synch Type None Usage Type Data wMaxPacketSize 0x0010 1x 16 bytes bInterval 8 can't get debug descriptor: Resource temporarily unavailable Device Status: 0x0000 (Bus Powered) ``` RE: Today in vendors slipping single bits (or single bit!) of information into weird places: I am *completely* certain that Google once made a USB-C audio adapter that has a *different USB PID* depending on whether it has something plugged into it. I am somewhat certain that it's 18d1:5025 with something plugged in, and 18d1:5029 without. If anyone has this adapter and is interested in this useless research, please send screenshots lsusb or device manager for this. Thank you so much. I need this.
Lori Emerson
Greg Egan
xero
Gateway of Last Resort
