1 files changed, 14 insertions, 1 deletions
diff --git a/sys/contrib/dev/acpica/components/hardware/hwtimer.c b/sys/contrib/dev/acpica/components/hardware/hwtimer.c
index 1a13f64..e103014 100644
--- a/sys/contrib/dev/acpica/components/hardware/hwtimer.c
+++ b/sys/contrib/dev/acpica/components/hardware/hwtimer.c
@@ -115,8 +115,14 @@ AcpiGetTimer (
         return_ACPI_STATUS (AE_BAD_PARAMETER);
     }
 
-    Status = AcpiHwRead (Ticks, &AcpiGbl_FADT.XPmTimerBlock);
+    /* ACPI 5.0A: PM Timer is optional */
 
+    if (!AcpiGbl_FADT.XPmTimerBlock.Address)
+    {
+        return_ACPI_STATUS (AE_SUPPORT);
+    }
+
+    Status = AcpiHwRead (Ticks, &AcpiGbl_FADT.XPmTimerBlock);
     return_ACPI_STATUS (Status);
 }
 
@@ -171,6 +177,13 @@ AcpiGetTimerDuration (
         return_ACPI_STATUS (AE_BAD_PARAMETER);
     }
 
+    /* ACPI 5.0A: PM Timer is optional */
+
+    if (!AcpiGbl_FADT.XPmTimerBlock.Address)
+    {
+        return_ACPI_STATUS (AE_SUPPORT);
+    }
+
     /*
      * Compute Tick Delta:
      * Handle (max one) timer rollovers on 24-bit versus 32-bit timers.