diff --git a/sys/x86/cpufreq/hwpstate_amd.c b/sys/x86/cpufreq/hwpstate_amd.c
--- a/sys/x86/cpufreq/hwpstate_amd.c
+++ b/sys/x86/cpufreq/hwpstate_amd.c
@@ -137,6 +137,11 @@
     "If enabled (1), limit administrative control of P-states to the value in "
     "CurPstateLimit");
 
+static bool	hwpstate_prefer_msr;
+SYSCTL_BOOL(_debug, OID_AUTO, hwpstate_prefer_msr, CTLFLAG_RDTUN,
+    &hwpstate_prefer_msr, 0,
+    "If enabled (1), use MSR instead of acpi_perf for P-state information");
+
 static device_method_t hwpstate_methods[] = {
 	/* Device interface */
 	DEVMETHOD(device_identify,	hwpstate_identify),
@@ -385,15 +390,17 @@
 				 * we can get _PSS info from acpi_perf
 				 * without going into ACPI.
 				 */
-				HWPSTATE_DEBUG(dev, "going to fetch info from acpi_perf\n");
-				error = hwpstate_get_info_from_acpi_perf(dev, perf_dev);
+				if (!hwpstate_prefer_msr) {
+					HWPSTATE_DEBUG(dev, "going to fetch info from acpi_perf\n");
+					error = hwpstate_get_info_from_acpi_perf(dev, perf_dev);
+				}
 			}
 		}
 	}
 
-	if (error == 0) {
+	if (error == 0 && !hwpstate_prefer_msr) {
 		/*
-		 * Now we get _PSS info from acpi_perf without error.
+		 * We got _PSS info from acpi_perf without error.
 		 * Let's check it.
 		 */
 		msr = rdmsr(MSR_AMD_10H_11H_LIMIT);
@@ -408,7 +415,7 @@
 	 * If we cannot get info from acpi_perf,
 	 * Let's get info from MSRs.
 	 */
-	if (error)
+	if (error || hwpstate_prefer_msr)
 		error = hwpstate_get_info_from_msr(dev);
 	if (error)
 		return (error);