The Arduino wiki has a page on getting an Arduino to work with Gentoo. It didn't work for me, so I'm posting what did work here. I'm hesitant to put this on the wiki page directly, because it would require removing a lot of information that was put there for a reason. But, here's what seems to have worked for me. Caveats: I've only tested with an Uno and a Leonardo; and in the process of getting them to work, I did a lot of other things that I don't think made a difference, but I don't remember what half of them were, so who knows?
How to do it
- Configure your kernel to enable
Device Drivers -> USB support -> USB Modem (CDC ACM) support. If you're not sure whether you have it, run
zgrep USB_ACM. If you do, there'll be a line
=m. It's okay to have as a module, and building a module is faster than recompiling your entire kernel and doesn't require a reboot. I'm not going to go into the process here, though.