CODEWITHSUNDEEP
linuxubuntuusbopenwrt
Allan K Liu
Allan K Liu

Reputation: 503

USB CDC ACM firmware compatilibities in different Linux

Due to development of IoT, I need a stable USB CDC ACM firmware in certain microcontroller. However I find the same device/firmware are not working well in all Linux OS.

I have tested the following boards/firmware:

  1. STM32F103C8T6_USBSerial from mbed community
  2. STM32F40X from mbed OS
  3. Keil USB stack for STM32F103
  4. STLinkV2 VCP from NUCLEO
  5. NXP LPC54114 CMSIS-DAP VCP
  6. STM32F103 CubeMX HAL (to be tested)
  7. Maple STM32F103 USB driver (to be tested)

And I tried to connect these boards to:

  1. OpenWRT
  2. Ubuntu 12.04 desktop/server
  3. Ubuntu 14.04 desktop/server
  4. Ubuntu 15.04 desktop

And firmware #1 doesn't work for #1/2/3 OS, while some other hardware may work with most of the OS. I have tried different tools, including gtkterm/echo/cat/stty/minicom/usbmon, python serial and lua.io. The result is same.

It seems both firmware and OS have issues. However, in some cases, we can not change too much in OS. But how to identify the root cause and get it fixed.

Update

I pasted my tracking record here.

dmesg

[  217.735609] usb 1-2: new full-speed USB device number 3 using ohci_hcd
[  218.232189] usb 1-2: New USB device found, idVendor=1f00, idProduct=2012
[  218.232195] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  218.232199] usb 1-2: Product: CDC DEVICE
[  218.232202] usb 1-2: Manufacturer: mbed.org
[  218.232205] usb 1-2: SerialNumber: 0123456789
[  218.298612] cdc_acm 1-2:1.0: ttyACM0: USB ACM device
[  218.320171] usbcore: registered new interface driver cdc_acm
[  218.320179] cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters

lsusb

Bus 001 Device 002: ID 80ee:0021 VirtualBox USB Tablet
Bus 001 Device 003: ID 1f00:2012  
Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

lsbusb -v

Bus 001 Device 003: ID 1f00:2012  
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            2 Communications
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0x1f00 
  idProduct          0x2012 
  bcdDevice            1.00
  iManufacturer           1 
  iProduct                2 
  iSerial                 3 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           75
    bNumInterfaces          2
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0x80
      (Bus Powered)
    MaxPower              100mA
    Interface Association:
      bLength                 8
      bDescriptorType        11
      bFirstInterface         0
      bInterfaceCount         2
      bFunctionClass          2 Communications
      bFunctionSubClass       2 Abstract (modem)
      bFunctionProtocol       0 None
      iFunction               0 
    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              0 
      CDC Header:
        bcdCDC               1.10
      CDC Call Management:
        bmCapabilities       0x03
          call management
          use DataInterface
        bDataInterface          1
      CDC ACM:
        bmCapabilities       0x06
          sends break
          line coding and serial state
      CDC Union:
        bMasterInterface        0
        bSlaveInterface         1 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval              16
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass        10 CDC Data
      bInterfaceSubClass      0 Unused
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 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     0x0040  1x 64 bytes
        bInterval               0

find /dev/bus

/dev/bus
/dev/bus/usb
/dev/bus/usb/001
/dev/bus/usb/001/003
/dev/bus/usb/001/002
/dev/bus/usb/001/001

USB devices info

ll /sys/bus/usb/devices
总用量 0
drwxr-xr-x 2 root root 0  1月 26 19:34 ./
drwxr-xr-x 4 root root 0  1月 26 19:34 ../
lrwxrwxrwx 1 root root 0  1月 26 19:34 1-0:1.0 -> ../../../devices/pci0000:00/0000:00:06.0/usb1/1-0:1.0/
lrwxrwxrwx 1 root root 0  1月 26 19:34 1-1 -> ../../../devices/pci0000:00/0000:00:06.0/usb1/1-1/
lrwxrwxrwx 1 root root 0  1月 26 19:34 1-1:1.0 -> ../../../devices/pci0000:00/0000:00:06.0/usb1/1-1/1-1:1.0/
lrwxrwxrwx 1 root root 0  1月 26 19:38 1-2 -> ../../../devices/pci0000:00/0000:00:06.0/usb1/1-2/
lrwxrwxrwx 1 root root 0  1月 26 19:41 1-2:1.0 -> ../../../devices/pci0000:00/0000:00:06.0/usb1/1-2/1-2:1.0/
lrwxrwxrwx 1 root root 0  1月 26 19:41 1-2:1.1 -> ../../../devices/pci0000:00/0000:00:06.0/usb1/1-2/1-2:1.1/
lrwxrwxrwx 1 root root 0  1月 26 19:34 usb1 -> ../../../devices/pci0000:00/0000:00:06.0/usb1/

cd /sys/bus/usb/devices/1-2
ll

ll
总用量 0
drwxr-xr-x 6 root root     0  1月 26 19:38 ./
drwxr-xr-x 7 root root     0  1月 26 19:34 ../
drwxr-xr-x 5 root root     0  1月 26 19:38 1-2:1.0/
drwxr-xr-x 5 root root     0  1月 26 19:38 1-2:1.1/
-rw-r--r-- 1 root root  4096  1月 26 19:54 authorized
-rw-r--r-- 1 root root  4096  1月 26 19:54 avoid_reset_quirk
-r--r--r-- 1 root root  4096  1月 26 19:38 bcdDevice
-rw-r--r-- 1 root root  4096  1月 26 19:54 bConfigurationValue
-r--r--r-- 1 root root  4096  1月 26 19:38 bDeviceClass
-r--r--r-- 1 root root  4096  1月 26 19:54 bDeviceProtocol
-r--r--r-- 1 root root  4096  1月 26 19:54 bDeviceSubClass
-r--r--r-- 1 root root  4096  1月 26 19:54 bmAttributes
-r--r--r-- 1 root root  4096  1月 26 19:54 bMaxPacketSize0
-r--r--r-- 1 root root  4096  1月 26 19:54 bMaxPower
-r--r--r-- 1 root root  4096  1月 26 19:54 bNumConfigurations
-r--r--r-- 1 root root  4096  1月 26 19:54 bNumInterfaces
-r--r--r-- 1 root root  4096  1月 26 19:38 busnum
-r--r--r-- 1 root root  4096  1月 26 19:54 configuration
-r--r--r-- 1 root root 65553  1月 26 19:38 descriptors
-r--r--r-- 1 root root  4096  1月 26 19:54 dev
-r--r--r-- 1 root root  4096  1月 26 19:38 devnum
-r--r--r-- 1 root root  4096  1月 26 19:54 devpath
lrwxrwxrwx 1 root root     0  1月 26 19:38 driver -> ../../../../../bus/usb/drivers/usb/
drwxr-xr-x 3 root root     0  1月 26 19:54 ep_00/
-r--r--r-- 1 root root  4096  1月 26 19:38 idProduct
-r--r--r-- 1 root root  4096  1月 26 19:38 idVendor
-r--r--r-- 1 root root  4096  1月 26 19:54 ltm_capable
-r--r--r-- 1 root root  4096  1月 26 19:38 manufacturer
-r--r--r-- 1 root root  4096  1月 26 19:54 maxchild
lrwxrwxrwx 1 root root     0  1月 26 19:54 port -> ../1-0:1.0/port2/
drwxr-xr-x 2 root root     0  1月 26 19:54 power/
-r--r--r-- 1 root root  4096  1月 26 19:38 product
-r--r--r-- 1 root root  4096  1月 26 19:54 quirks
-r--r--r-- 1 root root  4096  1月 26 19:38 removable
--w------- 1 root root  4096  1月 26 19:54 remove
-r--r--r-- 1 root root  4096  1月 26 19:38 serial
-r--r--r-- 1 root root  4096  1月 26 19:38 speed
lrwxrwxrwx 1 root root     0  1月 26 19:38 subsystem -> ../../../../../bus/usb/
-rw-r--r-- 1 root root  4096  1月 26 19:38 uevent
-r--r--r-- 1 root root  4096  1月 26 19:54 urbnum
-r--r--r-- 1 root root  4096  1月 26 19:54 version

cat virutal files

allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat authorized 
1
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat avoid_reset_quirk 
0
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat bcdDevice 
0100
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat bConfigurationValue 
1
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat bDeviceClass 
02
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat bDeviceProtocol 
00
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat bDeviceSubClass 
00
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat bmAttributes 
80
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat bMaxPacketSize0 
64
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat bMaxPower 
100mA
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat bNumConfigurations 
1
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat bNumInterfaces 
 2
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat busnum 
1
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat configuration 
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat descriptors 
@   K�2
                        $$$$�@  
�@@allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat dev
189:2
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat devnum
3
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat devpath 
2
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat idProduct 
2012
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat idVendor 
1f00
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat ltm_capable 
no
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat manufacturer 
mbed.org
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat maxchild 
0
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat product 
CDC DEVICE
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat quirks 
0x0
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat removable 
unknown
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat remove
cat: remove: 权限不够
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat serial 
0123456789
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat speed 
12
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat uevent 
MAJOR=189
MINOR=2
DEVNAME=bus/usb/001/003
DEVTYPE=usb_device
DRIVER=usb
PRODUCT=1f00/2012/100
TYPE=2/0/0
BUSNUM=001
DEVNUM=003
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat urbnum 
138
allankliu@allankliu-VirtualBox:/sys/bus/usb/devices/1-2$ cat version 
 1.10

Check /dev/ttyACM0

crw-rw----   1 root    dialout 166,   0  1月 26 19:38 ttyACM0

usbmon

sudo ls /sys/kernel/debug/usb/usbmon
[sudo] password for allankliu: 
0s  0u  1s  1t  1u

sudo cat /sys/kernel/debug/usb/devices
...

T:  Bus=01 Lev=01 Prnt=01 Port=01 Cnt=02 Dev#=  3 Spd=12   MxCh= 0
D:  Ver= 1.10 Cls=02(comm.) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=1f00 ProdID=2012 Rev= 1.00
S:  Manufacturer=mbed.org
S:  Product=CDC DEVICE
S:  SerialNumber=0123456789
C:* #Ifs= 2 Cfg#= 1 Atr=80 MxPwr=100mA
A:  FirstIf#= 0 IfCount= 2 Cls=02(comm.) Sub=02 Prot=00
I:* If#= 0 Alt= 0 #EPs= 1 Cls=02(comm.) Sub=02 Prot=01 Driver=cdc_acm
E:  Ad=81(I) Atr=03(Int.) MxPS=  64 Ivl=16ms
I:* If#= 1 Alt= 0 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=cdc_acm
E:  Ad=82(I) Atr=02(Bulk) MxPS=  64 Ivl=0ms
E:  Ad=02(O) Atr=02(Bulk) MxPS=  64 Ivl=0ms

device file system

/dev/ttyACM0 is generated as soon as the device is plugged in.

gtkterm

The device can be opened, but not output, regardless the baudrate.

Observation

  1. In lsusb, no product name is printed out, but working CDC devices also have same issue;
  2. In lsusb -v, error of Couldn't open device, some information will be missing, however even Linux hub has same problem.
  3. When cat /sys/bus/usb/devices/1-2/descriptor, it returns binary data, but other USB devices are same, it seems a binary file, anyway.

So far, based upon data, I can not find big differences or error from OS, but it has no output anyway, but it has output in Windows/Ubuntu 15 or later.

Next step, I will use wireshark/tcpdump to find out.

Update

After some labs, I found actually this STM32F103C8 (so-called bluepill) has already successfully emuerated. And the USB dongle has been supported in OpenWRT/Ubuntu12.04/14.04/16.04/18.04, but sometimes the device stalls for a while. After such pause, the communication is back to normal.

Pure firmware issue.

Upvotes: 1

Views: 7542

Answers (1)

David Grayson
David Grayson

Reputation: 87486

  • I would recommend getting a nice USB protocol analyzer like the Beagle USB 12 so you can look at the communication going between the device and the OS. You can study both the working case and the non-working case.
  • You should also run dmesg and look for messages from Linux's cdc-acm driver when you plug the device in. You can find out what kernel version you are running with uname -a and then look at the source code of the cdc-acm module in that kernel version.
  • You can see the USB descriptors of you device using lsusb -v and make sure they are valid.
  • You should also make sure you get a clear understanding of what symptoms your system has when it's not working, and use that to narrow your search for the problem. For example, if the /dev entry was not being created, that is a different type of problem than if your reads and writes to the port were failing.

Using the above methods you should be able to figure out what is wrong and fix it. This is almost certainly a firmware problem, not a hardware problem. I suspect there is something wrong with your USB descriptors so I'd start looking there first.

Upvotes: 0

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