What mraa version are you using? You can check this by typing opkg list-installed | grep mraa. Another way is to get into python and type the following lines:
Yes, I indeed used the isr_pin6.c test from GitHub (which sets the direction to MRAA_GPIO_IN,
and edge to MRAA_GPIO_EDGE_BOTH). When I read on the interrupt, it is always 1.
I suspect it may be catching only one edge (thus not getting any zero's even though I have
a toggling signal on the pin).
Incidentally, I updated mraa library to 0.6.2-13.