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尝试通过 USB 端口连接串行设备（3d 打印机），以便在 Android 设备（LOS 18.1/Android 11、3.18 内核）上与其（klipper 固件）进行通信。但我在 /dev/serial/ 中找不到它，它只显示为 /dev/ttyUSB0 和 /dev/bus/usb/001/00[^1] 并且我无法通过这些与它通信。我已经使用 ch341.c 驱动程序编译了内核。通过 Linux 部署从 chroot Debian 中执行“lsusb -v”会给出以下输出，有问题的设备称为“QinHeng Electronics CH340...”：
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 3.00
bDeviceClass 9 Hub
bDeviceSubClass 0
bDeviceProtocol 3
bMaxPacketSize0 9
idVendor 0x1d6b Linux Foundation
idProduct 0x0003 3.0 root hub
bcdDevice 3.18
iManufacturer 3 Linux 3.18.140-Swan-gcb3e40e597b0-dirty xhci-hcd
iProduct 2 xHCI Host Controller
iSerial 1 xhci-hcd.0.auto
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 0x001f
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xe0
Self Powered
Remote Wakeup
MaxPower 0mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 9 Hub
bInterfaceSubClass 0
bInterfaceProtocol 0 Full speed (or root) hub
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0004 1x 4 bytes
bInterval 12
bMaxBurst 0
Hub Descriptor:
bLength 12
bDescriptorType 42
nNbrPorts 1
wHubCharacteristic 0x000a
No power switching (usb 1.0)
Per-port overcurrent protection
bPwrOn2PwrGood 10 * 2 milli seconds
bHubContrCurrent 0 milli Ampere
bHubDecLat 0.0 micro seconds
wHubDelay 0 nano seconds
DeviceRemovable 0x00
Hub Port Status:
Port 1: 0000.02a0 5Gbps power Rx.Detect
Binary Object Store Descriptor:
bLength 5
bDescriptorType 15
wTotalLength 0x000f
bNumDeviceCaps 1
SuperSpeed USB Device Capability:
bLength 10
bDescriptorType 16
bDevCapabilityType 3
bmAttributes 0x02
Latency Tolerance Messages (LTM) Supported
wSpeedsSupported 0x0008
Device can operate at SuperSpeed (5Gbps)
bFunctionalitySupport 3
Lowest fully-functional device speed is SuperSpeed (5Gbps)
bU1DevExitLat 0 micro seconds
bU2DevExitLat 0 micro seconds
can't get debug descriptor: Resource temporarily unavailable
Device Status: 0x0001
Self Powered
Bus 001 Device 003: ID 1a86:7523 QinHeng Electronics CH340 serial converter
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 1.10
bDeviceClass 255 Vendor Specific Class
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x1a86 QinHeng Electronics
idProduct 0x7523 CH340 serial converter
bcdDevice 2.64
iManufacturer 0
iProduct 2 USB Serial
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 0x0027
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0x80
(Bus Powered)
MaxPower 98mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 3
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 1
bInterfaceProtocol 2
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 0x0020 1x 32 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 0x0020 1x 32 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0008 1x 8 bytes
bInterval 1
can't get debug descriptor: Resource temporarily unavailable
Device Status: 0x0000
(Bus Powered)
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 9 Hub
bDeviceSubClass 0
bDeviceProtocol 1 Single TT
bMaxPacketSize0 64
idVendor 0x1d6b Linux Foundation
idProduct 0x0002 2.0 root hub
bcdDevice 3.18
iManufacturer 3 Linux 3.18.140-Swan-gcb3e40e597b0-dirty xhci-hcd
iProduct 2 xHCI Host Controller
iSerial 1 xhci-hcd.0.auto
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 0x0019
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xe0
Self Powered
Remote Wakeup
MaxPower 0mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 9 Hub
bInterfaceSubClass 0
bInterfaceProtocol 0 Full speed (or root) hub
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0004 1x 4 bytes
bInterval 12
Hub Descriptor:
bLength 9
bDescriptorType 41
nNbrPorts 1
wHubCharacteristic 0x000a
No power switching (usb 1.0)
Per-port overcurrent protection
TT think time 8 FS bits
bPwrOn2PwrGood 10 * 2 milli seconds
bHubContrCurrent 0 milli Ampere
DeviceRemovable 0x00
PortPwrCtrlMask 0xff
Hub Port Status:
Port 1: 0000.0103 power enable connect
can't get device qualifier: Resource temporarily unavailable
can't get debug descriptor: Resource temporarily unavailable
Device Status: 0x0001
Self Powered
如何与串口设备通信？我还应该编译其他内核模块吗？较新的 Android 处理串行设备的方式是否与 Linux 不同？我见过其他人在 Android 上的 chrooted Linux 上运行这个固件，比如这里,这里,这里。所以这是有可能的，我只是错过了一些东西。我很高兴发布其他调试信息/日志。
答案1
/dev/ttyUSB0将是大多数 USB 转串口转换器的 Linux 内核默认名称，而/dev/serial/*可能是某些 udev 规则创建的别名。如果您的 Android 系统具有最小化的 ude 规则集，则它可能不包含生成/dev/serial/*别名的规则。
（/dev/ttyUSB0以及它的任何别名，如果存在）是 USB 转串行转换器的 Unix TTY 设备接口（基本上是串行端口 + 许多用于处理陈旧串行终端的可选功能）。如果转换芯片和实际的3D打印机之间存在实际的RS-232串行通信，则可能需要设置正确的串口参数才能成功通信。即使是最小的终端仿真器程序（例如）也picocom可能在这里有很大帮助，尽管您可能可以stty在必要时使用它来进行设置。
/dev/bus/usb/*/*另一方面，设备希望使用它们的程序能够了解 USB 总线的功能。实际上，程序很可能会使用该libusb库来处理这些设备。