ACPI 6.0 requires Processor Local X2APIC for all processors
ACPI Specification since version 6.0 (released in April 2015) requires Processor Local X2APIC structure for all processors (even those with ID < 255). We already support this, but we still report a warning:
Dec 21 22:17:07 test apix: [ID 248403 kern.warning] WARNING: apix: ignoring invalid entry in MADT: CPU 0 has X2APIC Id 0 (< 255)
This is just to remove such a warning from the
acpi_probe() function to maintain ACPI 6.0+ compatibility without noise.