Hi Anthony, Thanks for your dmesg log and acpidump result. (In reply to Anthony Agelastos from comment #17) > Created attachment 849033 [details] > This contains acpidump and dmesg info for 5.11 and 5.12 kernels. > > This compressed tarball contains output for `acpidump` and `dmesg` for the > 5.11 and 5.12 kernels. Base on dmesg log, I saw that the PmRef Cpu0Hwp SSDT be loaded on v5.11 kernel but not on v5.12 kernel. The table has defined _CPC method. I am looking at why is this Cpu0Hwp SSDT not loaded.