USB 调制解调器驱动程序 OpenWRT：ttyUSB0 断开连接

Question

问题是如何正确进行模式切换。来自 usb_modeswitch手动的：

在 Linux 上，大多数情况下驱动程序都以内核模块的形式提供，例如“usbserial”或“option”。但是，设备（WAN 加密狗）默认显示为“usb-storage”。usb_modeswitch 可以向已知启动模式切换的设备发送提供的批量消息（很可能是大容量存储命令）。

在我的 Linux 笔记本电脑上，加密狗曾经工作正常。因此，我查看了日志消息，发现模式切换“消息”与 OpenWRT 中使用的消息不同。

USB_ModeSwitch log from Wed Sep 12 12:19:46 PDT 2018
        ...OMITTED FOR CLARITY...
DefaultVendor=  0x1c9e
DefaultProduct= 0xf000
TargetVendor=   0x1c9e
TargetProductList="9000,9603,9605,9607,9900,9a00"
MessageContent="55534243123456788000000080000606f50402527000000000000000000000"
        ...OMITTED FOR CLARITY...
  found USB ID 1c9e:f000
   vendor ID matched
   product ID matched
 Found devices in default mode (1)
        ...OMITTED FOR CLARITY...
Looking for active drivers ...
 OK, driver detached
Set up interface 0
Use endpoint 0x01 for message sending ...
Trying to send message 1 to endpoint 0x01 ...
 OK, message successfully sent
        ...OMITTED FOR CLARITY...
Check success of mode switch for max. 20 seconds ...
        ...OMITTED FOR CLARITY...
 Read attributes ...
 All attributes matched
Mode switching was successful, found 1c9e:9605 (USB Modem: USB Modem)
        ...OMITTED FOR CLARITY...
All done, exit

OpenWRT 使用一个名为usbmode，这似乎是经典 usb_modeswitch 的精简版。配置文件位于/etc/usb-mode.json。默认配置对我来说不起作用，所以我用以下内容替换了原始文件的内容；

{
    "messages" : [
            "55534243123456788000000080000606f50402527000000000000000000000"
],
"devices" : {
            "1c9e:f000": {
                    "*": {
                            "t_vendor": 7326,
                            "t_product": [ 38405 ],
                            "msg": [ 0 ],
                            "wait": 5
                    }
            }
    }
}

重启路由器后，加密狗被正确检测到。以下是日志中的相关部分：

在 [ 17.576569] 和 [ 18.653216] 处，它显示为存储设备。在 [ 21.384065] 处，它断开连接（因为 modeswitch 命令）。最后在 [ 22.542980] 处，它被检测为调制解调器。

[   17.576569] usb-storage 1-1:1.0: USB Mass Storage device detected
[   17.622021] scsi host0: usb-storage 1-1:1.0
[   17.625508] usbcore: registered new interface driver usb-storage
[   17.726435] usbcore: registered new interface driver usbserial
[   17.730925] usbcore: registered new interface driver usbserial_generic
[   17.737547] usbserial: USB Serial support registered for generic
[   17.878689] xt_time: kernel timezone is -0000
[   17.904942] usbcore: registered new interface driver cdc_ether
[   18.200614] PPP generic driver version 2.4.2
[   18.225069] NET: Registered protocol family 24
[   18.248515] usbcore: registered new interface driver rndis_host
[   18.450180] usbcore: registered new interface driver option
[   18.454525] usbserial: USB Serial support registered for GSM modem (1-port)
    ...
[   18.653216] scsi 0:0:0:0: CD-ROM            USBModem Disk             2.31 PQ: 0 ANSI: 2
[   18.712241] kmodloader: done loading kernel modules from /etc/modules.d/*
[   21.384065] usb 1-1: USB disconnect, device number 2
[   21.885051] usb 1-1: new high-speed USB device number 3 using ci_hdrc
[   22.542980] option 1-1:1.0: GSM modem (1-port) converter detected
[   22.548046] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
[   22.555899] option 1-1:1.1: GSM modem (1-port) converter detected
[   22.560931] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
[   22.568813] option 1-1:1.2: GSM modem (1-port) converter detected
[   22.573936] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB2
[   22.581718] option 1-1:1.3: GSM modem (1-port) converter detected
[   22.586759] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB3

我们还可以看到productID已经从f000变成了9605，说明模式切换成功。

root@MrGhosh:~# lsusb
Bus 001 Device 003: ID 1c9e:9605 OMEGA TECHNOLOGY
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

root@MrGhosh:~# cat /sys/kernel/debug/usb/devices
...
T:  Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  3 Spd=480  MxCh= 0
D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=1c9e ProdID=9605 Rev= 0.00
S:  Manufacturer=USB Modem
S:  Product=USB Modem
S:  SerialNumber=1234567890ABCDEF
C:* #Ifs= 5 Cfg#= 1 Atr=e0 MxPwr=500mA
I:* If#= 0 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=option
E:  Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=01(O) Atr=02(Bulk) MxPS= 512 Ivl=4ms
I:* If#= 1 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=option
E:  Ad=82(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=4ms
I:* If#= 2 Alt= 0 #EPs= 2 Cls=ff(vend.) Sub=ff Prot=ff Driver=option
E:  Ad=83(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=03(O) Atr=02(Bulk) MxPS= 512 Ivl=4ms
I:* If#= 3 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=option
E:  Ad=84(I) Atr=03(Int.) MxPS=  64 Ivl=2ms
E:  Ad=85(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=04(O) Atr=02(Bulk) MxPS= 512 Ivl=4ms
I:* If#= 4 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage
E:  Ad=05(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E:  Ad=86(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms

Answer 1