Is Raspberry + mesa 7i92 possible

The title says it all, is this combination possible? should a need to add a second eth port to the RPi (maybe usb to eth)
txs!

I dont think its practical because the RPI doesn't have native Ethernet (only Ethernet over USB which is not real time)

Banana Pi then?

Possibly, I would do a ping test against a real time host (or a 7I92) and verify that its Ethernet driver is realtime capable
before wasting a lot of time however. Preempt-RT patched Realtek and Intel Ethernet MAC drivers are known to be real time capable, random ARM hardware: unknown...

So, the safest choice today is to use one the mesa with SPI ?

Unless you need low power or have very little space availabe, a PC with a real disk drive
is pretty much better in every way than the ARM platform for LinuxCNC

With a few exceptions, the ARM platforms suffer from cellphone-itus:

#1. Short product lifetime
#2. Bad documentation
#3. Kernel bugs that are never fixed until the product is obsolete
#4. Every new SOC is different so you start over at #1 every couple of years
#5. Often dismal graphics performance compared to X86

Basically the consumer embedded ARM chips are not a "platform"
in the same way a x86 PC is a platform

If you really want to use ARM, I would suggest Machinekit/Beaglebone

The Beaglebone uses an industrial SOC instead of a consumer tablet SOC
and has a couple built in real time processors(PRUs) that can do things like high
speed step generation and encoder counting so the beaglebone does not need a FPGA
for these capabilities.