All esp32 gpio “edge” interrupts may not be available

[UncleGrumpy]

The esp32 (other esp32-X chips may vary slightly) allows for 4 GPIO edge interrupts to be set per core. There are many more logic level interrupts available, so they are less likely to impact users… but there is a limited number of these per core as well.

Currently the driver does not keep track of which core an interrupt is set on. It is the luck of the draw which core will get the request to set the interrupt (it will be set on the core handling the request).

Since the first core is the default for much of the network stack it would make sense to prefer setting edge interrupts on core 2 (by default) until these 4 interrupts are consumed and add additional interrupts on core 1. We should also add a way for users to specify the core that an interrupt will be set.

For the time being this means only 4 edge interrupts are guaranteed to be available, but others may or may not be lucky enough to have the request handled by a core with free edge interrupts available, up to the system limit of 8.