diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index cb6066c809ea..9cb4d0c468eb 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -181,7 +181,8 @@ static bool advance_transaction(struct acpi_ec *ec)
 	u8 status;
 	bool wakeup = false;
 
-	pr_debug("===== %s =====\n", in_interrupt() ? "IRQ" : "TASK");
+	pr_debug("===== %s (%d) =====\n",
+		 in_interrupt() ? "IRQ" : "TASK", smp_processor_id());
 	status = acpi_ec_read_status(ec);
 	t = ec->curr;
 	if (!t)