ch341-uart ttyUSB0: usb_serial_generic_read_bulk_callback - urb stopped: -32

Long story short: I'm getting frequent(ish) but random USB disconnects while printing with CB1 + Klipper.

Are there known issues around the USB to serial hardware or kernel driver?
Or could this be caused by something else entirely, and if so, what exactly?

My prints get randomly stopped when Klipper disconnects and just leaves everything running.
However, I found the following in `dmesg`, which may prove useful:

```dmesg
[ 1792.333387] ch341-uart ttyUSB0: usb_serial_generic_read_bulk_callback - urb stopped: -32
[ 1792.365028] ch341-uart ttyUSB0: usb_serial_generic_write_bulk_callback - nonzero urb status: -71
[ 1792.369401] ch341-uart ttyUSB0: usb_serial_generic_write_bulk_callback - nonzero urb status: -71
[ 1792.373966] ch341-uart ttyUSB0: usb_serial_generic_write_bulk_callback - nonzero urb status: -71
[ 1792.378273] ch341-uart ttyUSB0: usb_serial_generic_write_bulk_callback - nonzero urb status: -71
[ 1792.382386] usb 2-1-port2: disabled by hub (EMI?), re-enabling...
[ 1792.382425] usb 2-1.2: USB disconnect, device number 3
[ 1792.382909] usb 2-1.2: ch341_read_int_callback - usb_submit_urb failed: -19
[ 1792.383588] ch341-uart ttyUSB0: ch341-uart converter now disconnected from ttyUSB0
[ 1792.383674] ch341 2-1.2:1.0: device disconnected
[ 1792.727203] usb 2-1.2: new full-speed USB device number 4 using ehci-platform
[ 1792.940276] usb 2-1.2: New USB device found, idVendor=1a86, idProduct=7523, bcdDevice= 2.64
[ 1792.940308] usb 2-1.2: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[ 1792.940317] usb 2-1.2: Product: USB Serial
[ 1792.941092] ch341 2-1.2:1.0: ch341-uart converter detected
[ 1792.943021] usb 2-1.2: ch341-uart converter now attached to ttyUSB1
[ 1792.943540] sunxi-hdmi soc:hdmi-audio@1: snd_soc_register_card failed
[ 1966.718649] usb 2-1.2: USB disconnect, device number 4
[ 1966.719209] ch341-uart ttyUSB1: ch341-uart converter now disconnected from ttyUSB1
[ 1966.719279] ch341 2-1.2:1.0: device disconnected
[ 1971.351980] usb 2-1.2: new full-speed USB device number 5 using ehci-platform
[ 1971.581214] usb 2-1.2: New USB device found, idVendor=1a86, idProduct=7523, bcdDevice= 2.64
[ 1971.581245] usb 2-1.2: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[ 1971.581255] usb 2-1.2: Product: USB Serial
[ 1971.582028] ch341 2-1.2:1.0: ch341-uart converter detected
[ 1971.583260] usb 2-1.2: ch341-uart converter now attached to ttyUSB1
[ 1971.584366] sunxi-hdmi soc:hdmi-audio@1: snd_soc_register_card failed
[ 1983.600963] usb 2-1.2: USB disconnect, device number 5
[ 1983.601533] ch341-uart ttyUSB1: ch341-uart converter now disconnected from ttyUSB1
[ 1983.601612] ch341 2-1.2:1.0: device disconnected
[ 2000.560123] usb 2-1.2: new full-speed USB device number 6 using ehci-platform
[ 2000.790010] usb 2-1.2: New USB device found, idVendor=1a86, idProduct=7523, bcdDevice= 2.64
[ 2000.790041] usb 2-1.2: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[ 2000.790051] usb 2-1.2: Product: USB Serial
[ 2000.792643] ch341 2-1.2:1.0: ch341-uart converter detected
[ 2000.794619] usb 2-1.2: ch341-uart converter now attached to ttyUSB1
[ 2000.795116] sunxi-hdmi soc:hdmi-audio@1: snd_soc_register_card failed
```

Start with the supplied dmesg output, focusing on the ch341-uart errors, USB disconnects, and the hub's “disabled by hub (EMI?)” message. Reproduce the failure while printing with CB1 and Klipper, then compare the behavior across the USB-to-serial hardware, cable, port, and kernel driver. Done means identifying a specific cause and a confirmed corrective action, but the issue does not name a source file or test.

Written by the indexing model from the issue text.