A3 and Google AOA mode

jonsmirl · Post time 2018-11-3 09:58:17

Google AOA mode does not function on the A1 Pro. I'm hoping that it will work on the A3.
https://source.android.com/devices/accessories/protocol

There is a tiny program that will check if the mode functions correctly.
https://github.com/gibsson/linux-adk

When this program fails on the A1 Pro, you will see this in your Linux host logs...
95154.486707] usb 1-5.1: Product: A1_PRO
[95154.486713] usb 1-5.1: Manufacturer: A-gold
[95154.486718] usb 1-5.1: SerialNumber: 0123456789ABCDEF
[95156.647795] usb 1-5.1: USB disconnect, device number 41
[95157.017964] usb 1-5.1: new high-speed USB device number 42 using xhci_hcd
[95157.122812] usb 1-5.1: New USB device found, idVendor=18d1, idProduct=2d03
[95157.122823] usb 1-5.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[95157.122830] usb 1-5.1: Product: A1_PRO
[95157.122836] usb 1-5.1: Manufacturer: A-gold
[95157.122841] usb 1-5.1: SerialNumber: 0123456789ABCDEF
[95157.124251] usb 1-5.1: 1:1: add audio endpoint 0x81
[95157.160158] usb 1-5.1: 1:1: usb_set_interface failed (-32)
[95157.161030] usb 1-5.1: 1:1: usb_set_interface failed (-32)
[95157.161851] usb 1-5.1: 1:1: usb_set_interface failed (-32)
[95157.163121] usb 1-5.1: 1:1: usb_set_interface failed (-32)
[95157.164489] usb 1-5.1: 1:1: usb_set_interface failed (-32)

Here's what the log looks like when it works...

[95584.714759] usb 1-2: Product: Pixel
[95584.714765] usb 1-2: Manufacturer: Google
[95584.714771] usb 1-2: SerialNumber: FA68Z0309184
[95586.782233] usb 1-2: USB disconnect, device number 48
[95587.309479] usb 1-2: new high-speed USB device number 49 using xhci_hcd
[95587.458468] usb 1-2: New USB device found, idVendor=18d1, idProduct=2d03
[95587.458478] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[95587.458485] usb 1-2: Product: Pixel
[95587.458490] usb 1-2: Manufacturer: Google
[95587.458496] usb 1-2: SerialNumber: FA68Z0309184
[95587.459886] usb 1-2: 1:1: add audio endpoint 0x82
----> A1 pro failed here
[95587.492151] usb 1-2: setting usb interface 1:1
[95587.495659] usb 1-2: setting usb interface 1:1
[95587.502216] usb 1-2: setting usb interface 1:1
[95587.506349] usb 1-2: Starting data EP @00000000d8f304ed
[95593.402794] usb 1-2: setting usb interface 1:1
[95593.403469] usb 1-2: Starting data EP @00000000d8f304ed
jonsmirl@ares:~/aosp/linux-adk$

Google AoA mode is used by docking stations with external speakers. It is also used by older cars which pre-date Android Auto.

jonsmirl · Post time 2018-12-7 00:58:56

Edited by jonsmirl at 2018-12-7 01:05

Unfortunately AoA mode is still broken in the A3. This is a bug in the MTK kernel driver for USB audio. The dock is failing to open the USB audio protocol over the USB port. This works on other Mediatek chips, of the phones I have only the MT6739 fails. Our application is a device test farm, redirecting the audio over a USB audio connection is how we test the sound output of the device under test. Because of this bug we can't run any tests on Umidigi A3 or A1.

[223786.572463] usb 1-1: new high-speed USB device number 13 using xhci_hcd
[223786.721641] usb 1-1: New USB device found, idVendor=0e8d, idProduct=2008
[223786.721643] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[223786.721645] usb 1-1: Product: A3
[223786.721647] usb 1-1: Manufacturer: UMIDIGI
[223786.721648] usb 1-1: SerialNumber: A3201809012173
[223847.009118] usb 1-1: reset high-speed USB device number 13 using xhci_hcd
[223847.285054] usb 1-1: reset high-speed USB device number 13 using xhci_hcd
[223880.928622] usb 1-1: USB disconnect, device number 13
[223881.313053] usb 1-1: new high-speed USB device number 14 using xhci_hcd
[223881.461820] usb 1-1: New USB device found, idVendor=18d1, idProduct=2d04
[223881.461826] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[223881.461830] usb 1-1: Product: A3
[223881.461834] usb 1-1: Manufacturer: UMIDIGI
[223881.461837] usb 1-1: SerialNumber: A3201809012173
[223881.496477] usbcore: registered new interface driver snd-usb-audio
[223881.518553] usb 1-1: 2:1: usb_set_interface failed (-32)
[223881.520081] usb 1-1: 2:1: usb_set_interface failed (-32)
[223881.521077] usb 1-1: 2:1: usb_set_interface failed (-32)
[223881.522552] usb 1-1: 2:1: usb_set_interface failed (-32)
[223881.523878] usb 1-1: 2:1: usb_set_interface failed (-32)

jonsmirl · Post time 2019-1-4 10:36:15

Can you please forward this over to your software developers....

When the kernel for the A3 was built, did USB audio support get turned off accidentally?
This might not be working simply because support for it was turned off.

It is supposed to be turned on:
jonsmirl@ares:~/aosp/mtk8/kernel-4.4/arch/arm64/configs$ grep SND_USB_AUDIO *
evb6771_64_emmc_debug_defconfig:CONFIG_SND_USB_AUDIO=y
evb6771_64_emmc_defconfig:CONFIG_SND_USB_AUDIO=y
evb6771_64_emmc_mhl_debug_defconfig:CONFIG_SND_USB_AUDIO=y
evb6771_64_emmc_mhl_defconfig:CONFIG_SND_USB_AUDIO=y
k39tv1_64_bsp_debug_defconfig:CONFIG_SND_USB_AUDIO=y
k39tv1_64_bsp_defconfig:CONFIG_SND_USB_AUDIO=y
k63v1_64_bsp_debug_defconfig:CONFIG_SND_USB_AUDIO=y

Turning on USB audio enables SND_PCM

config SND_USB_AUDIO
      tristate "USB Audio/MIDI driver"
      select SND_HWDEP
      select SND_RAWMIDI
      select SND_PCM
      select BITREVERSE

These #Ifdef then turn on the AOA USB audio support.

jonsmirl@ares:~/aosp/mtk8/kernel-4.4/drivers/usb/gadget$ grep PCM android.c
#ifdef CONFIG_SND_PCM
#ifdef CONFIG_SND_PCM

The audio interface is listed in the USB descriptors, when our code tries to turn it on, it errors out with -EPIPE. That would happen if the code in android.c was turned off by the IFDEFs and not built. This is code should always be turned on except in something like a watch with no USB audio.

Bus 001 Device 029: ID 18d1:2d05 Google Inc.
Device Descriptor:
  bLength             18
  bDescriptorType       1
  bcdUSB             2.00
  bDeviceClass          0 (Defined at Interface level)
  bDeviceSubClass       0
  bDeviceProtocol       0
  bMaxPacketSize0       64
  idVendor          0x18d1 Google Inc.
  idProduct       0x2d05
  bcdDevice          2.23
  iManufacturer          1 A-gold
  iProduct             2 A1_PRO
  iSerial                3 0123456789ABCDEF
  bNumConfigurations    1
  Configuration Descriptor:
bLength                9
bDescriptorType       2
wTotalLength       156
bNumInterfaces       4
bConfigurationValue    1
iConfiguration       4 accessory_audiosource_adb
bmAttributes       0x80
   (Bus Powered)
MaxPower             500mA
Interface Descriptor:
   bLength                9
   bDescriptorType       4
   bInterfaceNumber       0
   bAlternateSetting    0
   bNumEndpoints          2
   bInterfaceClass    255 Vendor Specific Class
   bInterfaceSubClass 255 Vendor Specific Subclass
   bInterfaceProtocol    0
   iInterface             5 Android Accessory Interface
   Endpoint Descriptor:
      bLength                7
      bDescriptorType       5
      bEndpointAddress    0x81  EP 1 IN
      bmAttributes          2
      Transfer Type          Bulk
      Synch Type             None
      Usage Type             Data
      wMaxPacketSize    0x0200  1x 512 bytes
      bInterval             0
   Endpoint Descriptor:
      bLength                7
      bDescriptorType       5
      bEndpointAddress    0x01  EP 1 OUT
      bmAttributes          2
      Transfer Type          Bulk
      Synch Type             None
      Usage Type             Data
      wMaxPacketSize    0x0200  1x 512 bytes
      bInterval             0
Interface Descriptor:
   bLength                9
   bDescriptorType       4
   bInterfaceNumber       1
   bAlternateSetting    0
   bNumEndpoints          0
   bInterfaceClass       1 Audio
   bInterfaceSubClass    1 Control Device
   bInterfaceProtocol    0
   iInterface             0
   AudioControl Interface Descriptor:
      bLength             10
      bDescriptorType       36
      bDescriptorSubtype    1 (HEADER)
      bcdADC             1.00
      wTotalLength          40
      bInCollection          2
      baInterfaceNr( 0)    1
      baInterfaceNr( 1)    2
   AudioControl Interface Descriptor:
      bLength             12
      bDescriptorType       36
      bDescriptorSubtype    2 (INPUT_TERMINAL)
      bTerminalID          1
      wTerminalType    0x0201 Microphone
      bAssocTerminal       0
      bNrChannels          2
      wChannelConfig    0x0003
      Left Front (L)
      Right Front (R)
      iChannelNames          0
      iTerminal             0
   AudioControl Interface Descriptor:
      bLength                9
      bDescriptorType       36
      bDescriptorSubtype    3 (OUTPUT_TERMINAL)
      bTerminalID          3
      wTerminalType    0x0101 USB Streaming
      bAssocTerminal       2
      bSourceID             2
      iTerminal             0
   AudioControl Interface Descriptor:
      bLength                9
      bDescriptorType       36
      bDescriptorSubtype    6 (FEATURE_UNIT)
      bUnitID                2
      bSourceID             1
      bControlSize          2
      bmaControls( 0)    0x00
      bmaControls( 0)    0x00
      iFeature             0
Interface Descriptor:
   bLength                9
   bDescriptorType       4
   bInterfaceNumber       2
   bAlternateSetting    0
   bNumEndpoints          0
   bInterfaceClass       1 Audio
   bInterfaceSubClass    2 Streaming
   bInterfaceProtocol    0
   iInterface             0
Interface Descriptor:
   bLength                9
   bDescriptorType       4
   bInterfaceNumber       2
   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          1
      bDelay                1 frames
      wFormatTag             1 PCM
   AudioStreaming Interface Descriptor:
      bLength             11
      bDescriptorType       36
      bDescriptorSubtype    2 (FORMAT_TYPE)
      bFormatType          1 (FORMAT_TYPE_I)
      bNrChannels          2
      bSubframeSize          2
      bBitResolution       16
      bSamFreqType          1 Discrete
      tSamFreq[ 0]       44100
   Endpoint Descriptor:
      bLength                9
      bDescriptorType       5
      bEndpointAddress    0x82  EP 2 IN
      bmAttributes          13
      Transfer Type          Isochronous
      Synch Type             Synchronous
      Usage Type             Data
      wMaxPacketSize    0x0100  1x 256 bytes
      bInterval             4
      bRefresh             0
      bSynchAddress          0
      AudioControl Endpoint Descriptor:
      bLength                7
      bDescriptorType       37
      bDescriptorSubtype    1 (EP_GENERAL)
      bmAttributes       0x01
         Sampling Frequency
      bLockDelayUnits       1 Milliseconds
      wLockDelay             1 Milliseconds
Interface Descriptor:
   bLength                9
   bDescriptorType       4
   bInterfaceNumber       3
   bAlternateSetting    0
   bNumEndpoints          2
   bInterfaceClass    255 Vendor Specific Class
   bInterfaceSubClass    66
   bInterfaceProtocol    1
   iInterface             6 ADB Interface
   Endpoint Descriptor:
      bLength                7
      bDescriptorType       5
      bEndpointAddress    0x02  EP 2 OUT
      bmAttributes          2
      Transfer Type          Bulk
      Synch Type             None
      Usage Type             Data
      wMaxPacketSize    0x0200  1x 512 bytes
      bInterval             0
   Endpoint Descriptor:
      bLength                7
      bDescriptorType       5
      bEndpointAddress    0x83  EP 3 IN
      bmAttributes          2
      Transfer Type          Bulk
      Synch Type             None
      Usage Type             Data
      wMaxPacketSize    0x0200  1x 512 bytes
      bInterval             0
Device Qualifier (for other device speed):
  bLength             10
  bDescriptorType       6
  bcdUSB             2.00
  bDeviceClass          0 (Defined at Interface level)
  bDeviceSubClass       0
  bDeviceProtocol       0
  bMaxPacketSize0       64
  bNumConfigurations    1
Device Status:    0x0000
  (Bus Powered)