在Linux系统有如下报错，或导致串口号异常变化

[235788.049659] usb usb3-port9: disabled by hub (EMI?), re-enabling...

[235788.049664] usb 3-9: USB disconnect, device number 5

[235788.050135] usb_ch9344 3-9:1.0: usb_bulk_msg(send) failed, err -19

[235788.050138] usb_ch9344 3-9:1.0: usb_bulk_msg(send) failed, err -19

[235788.050139] usb_ch9344 3-9:1.0: usb_bulk_msg(send) failed, err -19

[235788.050139] usb_ch9344 3-9:1.0: usb_bulk_msg(send) failed, err -19

[235788.050154] usb_ch9344 3-9:1.0: usb_bulk_msg(send) failed, err -19

[235788.050155] usb_ch9344 3-9:1.0: usb_bulk_msg(send) failed, err -19

[235788.050157] usb_ch9344 3-9:1.0: usb_bulk_msg(send) failed, err -19

[235788.050158] usb_ch9344 3-9:1.0: usb_bulk_msg(send) failed, err -19

[235788.050389] usb_ch9344 3-9:1.0: ch9344 usb device disconnect.

[235788.273149] usb 3-9: new high-speed USB device number 30 using xhci_hcd

[235788.399455] usb 3-9: New USB device found, idVendor=1a86, idProduct=55d9, bcdDevice= 1.36

[235788.399460] usb 3-9: New USB device strings: Mfr=1, Product=2, SerialNumber=0

[235788.399461] usb 3-9: Product: USB2.0 To Multi Serial Ports

[235788.399463] usb 3-9: Manufacturer: wch.cn

[235788.402262] usb_ch9344 3-9:1.0: ttyCH9344USB from 8 - 15: ch9344 device attached.

各路大神，有遇到过的吗

您好，如上信息提示和硬件工作状态有关，即USB通讯不稳定导致。出现串口变号的根本原因是：打开串口节点的时候USB硬件发生了物理掉线。

可检查设计原理图和PCB，如外部使用了延长线连接，那么可尝试缩短线材/使用带屏蔽线材等。