cpuidle driver not working

[rschoene]

As stated in #1, we just got a new Cavium Thunder X2 system. However, the idle driver is set to none, which certainly adds to the idle power consumption of the system.
This might be related to an invalid/incomplete device tree.
We were able to compile the device tree in master/arch/arm64/boot/dts/cavium/thunder2-99xx.dtsi. However the stub (

thunderx-linux/arch/arm64/boot/dts/cavium/thunder2-99xx.dtsi

Line 24 in 265c254

cpus {

) only holds 4 CPUs, and is annotated with just 4 cpus now, 128 needed in full config. When trying to pass this during boot, the system stucks during EFI stub.

Could you provide a device tree that works for Thunder X2 CN9975 systems?

The behavior (idle not working by default) can be seen with Linux kernels 4.15, 5.0, and 5.2.