OnePlus One (oneplus-bacon)
There is a bug whereby the screen is not automatically refreshed. To work around this, run the following command as root on the device:
# while [ ! ]; do cat /sys/class/graphics/fb0/modes > /sys/class/graphics/fb0/mode; done
Julian Goldsmith is currently working on mainlining the OnePlus One, based on flacks's initial DTS. Right now, he's using a fork of linux-postmarketos, and is trying to get hardware-accelerated graphics up and running.
The Adreno 330 GPU is supported by Freedreno. The firmware is required, and is available in the adreno-firmware package.
Julian Goldsmith currently has partially-working graphics support on mainline. The GPU is usable, but the display doesn't properly update. The issue most likely involves clock or regulator settings somehow.
oFono support shouldn't take too much to get up and running. Adding the remoteproc node, using qmictl (possibly more utilities), and using a patched oFono should get basic support up and running.
WiFi and Bluetooth
WiFi and Bluetooth are working, but aren't fully tested. They are most likely flakey.
Entering fastboot mode
From a power off state, hold the volume up and power buttons until the device vibrates. The display should then light up and say "Fastboot Mode".