Always show IP address briefly when booting

[jlauha]

If an autoplay playlist is used in a vanilla RPi, it can be difficult to determine IP address of the device. (Seems arp -a doesn't work in some cases?)

It'd be very helpful if the IP address would always be shown for a few seconds, if one is acquired at the boot time (or very soon after that). That is, before the autoplayed playlist is started, same way it would be shown as status display if there are no media to play at all.

[fabled]

We could show it as overlay if requested. Though, IP can change or be configured any time after boot depending on various things. I'd rather not do this as it might show the IP in unexpected situations.

There's other reliable ways to detect the IP from local network like doing ping sweep (nmap -sn) and then consulting arp table. Another option is to add multicast group which RAME listens - this enables finding the devices reliably with the multicast group address.

[jlauha]

I wouldn't want an overlay to show up whenever IP changes, as it would inevitably show in some unwanted case.

The particular situation where I hoped for the "boot time" feature was when needing to re-configure a vanilla RPi (running the clock util w/autoplay). So booting that RPi repeatedly wasn't an issue, meaning boot-time IP in HDMI out would've been enough. And for some reason "arp -a" in that particular case wouldn't show the ip even if that has worked beforehand (still a bit unsure why). In that case I ended up putting the SD card to computer and reading the config from the LBU.

Having an utility which would reliably list all devices would indeed be useful, but maybe a bit overkill (would be basically needed for multiple platforms). So far I've thought that "arp -a" (and grep for b8.27.eb) would be almost the same, i.e. finding all RPis.