Fix usb enumeration stage error for some device (IDFGH-9778)

[20051231]

Fix enumeration process crashed with stall status when enumerating devices which return bConfigurationValue with non standard value in the configuration description.

I encounter the bug when I try to connect a serial device from Netchip Technology. The device responses the request for first configuration with bConfigurationValue = 2. But in current code, the config_num is hardcoded to be ENUM_CONFIG_INDEX + 1 which is 1.

❯ lsusb -vd 0525:a4a7

Bus 001 Device 050: ID 0525:a4a7 Netchip Technology, Inc. Linux-USB Serial Gadget (CDC ACM mode)
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            2 Communications
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0x0525 Netchip Technology, Inc.
  idProduct          0xa4a7 Linux-USB Serial Gadget (CDC ACM mode)
  bcdDevice           24.18
  iManufacturer           1 Linux 2.6.39 with atmel_usba_udc
  iProduct                2 Gadget Serial v2.4
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x004b
    bNumInterfaces          2
    bConfigurationValue     2
    iConfiguration          3 
    bmAttributes         0xc0
      Self Powered
    MaxPower                2mA
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         0
      bInterfaceCount         2
      bFunctionClass          2 Communications
      bFunctionSubClass       2 Abstract (modem)
      bFunctionProtocol       1 AT-commands (v.25ter)
      iFunction               6 
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         2 Communications
      bInterfaceSubClass      2 Abstract (modem)
      bInterfaceProtocol      1 AT-commands (v.25ter)
      iInterface              4 
      CDC Header:
        bcdCDC               1.10
      CDC Call Management:
        bmCapabilities       0x00
        bDataInterface          1
      CDC ACM:
        bmCapabilities       0x02
          line coding and serial state
      CDC Union:
        bMasterInterface        0
        bSlaveInterface         1 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x000a  1x 10 bytes
        bInterval               9
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass        10 CDC Data
      bInterfaceSubClass      0 
      bInterfaceProtocol      0 
      iInterface              5 
      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     0x02  EP 2 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0

Here is the pcapng when I connect the device into PC.
usbmon.zip

[CLAassistant]

All committers have signed the CLA.

[Alvin1Zhang]

Thanks for your contribution.

[roma-jam]

Hi @20051231,
Thanks for the PR.

There is another ticket here which is also related to the configuration value.
For fully support the variety of configurations there should be a way to choose preferable one to work with and this option should also depend on bNumConfigurations value from device descriptor.

[Dazza0]

@20051231 Thank you for your contribution, Changes LGTM. I'll add an extra commit to update some comments and docs.

[Dazza0]

sha=9d1c8f4f1815ce1d4bcea32ab7ef2cb830e90a08