RPI3 Fixes

USB Issues

With the RPi3 it can have an issue with it's USB Controller when used in realtime.

• https://forums.raspberrypi.com/viewtopic.php?t=159170
• https://www.osadl.org/Single-View.111+M5c03315dc57.0.html
• https://www.osadl.org/monitoring/patches/rbs3s/usb-dwc_otg-fix-system-lockup-when-interrupts-are-threaded.patch.html

One workaround is to add the following to /boot/cmdline.txt

dwc_otg.fiq_enable=0 dwc_otg.fiq_fsm_enable=0

There was also another suggestion to also try dwc_otg.nak_holdoff=0
After rebooting the state can be checked with:

dmesg | grep otg
# Look for "dwc_otg: FIQ disabled"