1 files changed, 3 insertions, 1 deletions

diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c
index e69182fd01cf..4b28159e0421 100644
--- a/arch/x86/kernel/acpi/cstate.c
+++ b/arch/x86/kernel/acpi/cstate.c
@@ -87,7 +87,9 @@ static long acpi_processor_ffh_cstate_probe_cpu(void *_cx)
         num_cstate_subtype = edx_part & MWAIT_SUBSTATE_MASK;
 
         retval = 0;
-        if (num_cstate_subtype < (cx->address & MWAIT_SUBSTATE_MASK)) {
+        /* If the HW does not support any sub-states in this C-state */
+        if (num_cstate_subtype == 0) {
+                pr_warn(FW_BUG "ACPI MWAIT C-state 0x%x not supported by HW (0x%x)\n", cx->address, edx_part);
                 retval = -1;
                 goto out;
         }