Every now and then I see in dmesg:
[Wed May 20 14:03:16 2020] cdc_ether 1-6.2:1.0 usb0: unregister 'cdc_ether' usb-0000:00:14.0-6.2, CDC Ethernet Device
[Wed May 20 14:03:25 2020] usb usb1-port6: disabled by hub (EMI?), re-enabling...
[Wed May 20 14:03:25 2020] usb 1-6: USB disconnect, device number 85
[Wed May 20 14:03:25 2020] cdc_acm 1-6.3:1.1: acm_ctrl_irq - usb_submit_urb failed: -19
[Wed May 20 14:03:25 2020] usb 1-6-port2: attempt power cycle
[Wed May 20 14:03:26 2020] usb 1-6.3: USB disconnect, device number 86
[Wed May 20 14:03:26 2020] cdc_acm 1-6.3:1.1: failed to set dtr/rts
[Wed May 20 14:03:26 2020] usb 1-6: new high-speed USB device number 94 using xhci_hcd
[Wed May 20 14:03:27 2020] hub 1-6:1.0: USB hub found
[Wed May 20 14:03:27 2020] hub 1-6:1.0: 3 ports detected
[Wed May 20 14:03:27 2020] usb 1-6.2: new high-speed USB device number 95 using xhci_hcd
[Wed May 20 14:03:27 2020] cdc_ether 1-6.2:1.0 usb0: register 'cdc_ether' at usb-0000:00:14.0-6.2, CDC Ethernet Device, 7e:1d:06:c0:3f:3c
[Wed May 20 14:03:27 2020] usb 1-6.3: new high-speed USB device number 96 using xhci_hcd
[Wed May 20 14:03:27 2020] cdc_acm 1-6.3:1.1: ttyACM0: USB ACM device
This (EMI?) disconnect causes 2 things.
1) I loose the TTY temporarily and have to reconnect.
2) After reconnect there are garbage chars on the gadget side, such as:
h�^@^@� ^@^@� ^@
or
X���)H��4Ğ^���
which causes confusion on for the tty/bash on the gadget.
The disconnect is mostly just annoying but the garbage chars are a major pain, one cannot trust
that cmds are understod. Is there a bug in ttyACM driver causing these?
Jocke
