Snap interfaces serial-port error "serial-port path attribute must be a valid device node"

ijohnson · January 6, 2020, 5:03pm

The current pattern is described as follows here:

snapcore/snapd/blob/master/interfaces/builtin/serial_port.go#L66-L75


// Pattern to match allowed serial device nodes, path attributes will be
// compared to this for validity when not using udev identification
// Known device node patterns we need to support
//  - ttyUSBX  (UART over USB devices)
//  - ttyACMX  (ACM modem devices )
//  - ttyXRUSBx  (Exar Corp. USB UART devices)
//  - ttySX (UART serial ports)
//  - ttyOX (UART serial ports on ARM)
//  - ttymxcX (serial ports on i.mx6UL)
//  - ttySCX (NXP SC16IS7xx serial devices)

It’s easy enough to add a rule to allow /dev/ttyGPS or /dev/ttyLP1, but I’m not familiar with those device nodes never having seen them before. Are /dev/ttyGPS and /dev/ttyLP1 device nodes specific to your model/board or this is a generic access? I couldn’t find any reference to /dev/ttyGPS from some simple searching (and nothing in https://www.kernel.org/doc/Documentation/admin-guide/devices.txt), but I saw some references to /dev/ttyLP* in other random searches.