diff --git a/drivers/platform/x86/mxm-wmi.c b/drivers/platform/x86/mxm-wmi.c
index 9a19fbd2f734..9a457956025a 100644
--- a/drivers/platform/x86/mxm-wmi.c
+++ b/drivers/platform/x86/mxm-wmi.c
@@ -35,13 +35,11 @@ int mxm_wmi_call_mxds(int adapter)
 		.xarg = 1,
 	};
 	struct acpi_buffer input = { (acpi_size)sizeof(args), &args };
-	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
 	acpi_status status;
 
 	printk("calling mux switch %d\n", adapter);
 
-	status = wmi_evaluate_method(MXM_WMMX_GUID, 0x0, adapter, &input,
-				     &output);
+	status = wmi_evaluate_method(MXM_WMMX_GUID, 0x0, adapter, &input, NULL);
 
 	if (ACPI_FAILURE(status))
 		return status;
@@ -60,13 +58,11 @@ int mxm_wmi_call_mxmx(int adapter)
 		.xarg = 1,
 	};
 	struct acpi_buffer input = { (acpi_size)sizeof(args), &args };
-	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
 	acpi_status status;
 
 	printk("calling mux switch %d\n", adapter);
 
-	status = wmi_evaluate_method(MXM_WMMX_GUID, 0x0, adapter, &input,
-				     &output);
+	status = wmi_evaluate_method(MXM_WMMX_GUID, 0x0, adapter, &input, NULL);
 
 	if (ACPI_FAILURE(status))
 		return status;