FYI, passing the kernel boot param 'processor.max_cstate=2' will work ONLY if you have the ACPI Processor compiled into the kernel (aka NOT as a module).
Recompiling the kernel with CONFIG_ACPI_PROCESSOR=y will allow you to set the max_cstate upon boot.
This is probably not an acceptable solution for the majority of users, but it is a workaround.
FYI, passing the kernel boot param 'processor. max_cstate= 2' will work ONLY if you have the ACPI Processor compiled into the kernel (aka NOT as a module). ACPI_PROCESSOR= y will allow you to set the max_cstate upon boot.
Recompiling the kernel with CONFIG_
This is probably not an acceptable solution for the majority of users, but it is a workaround.