diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index ecc74fa4bfde8a55d9fee00d96ae5ae4123560e9..748129c85f3543ec852a8654afd0520e2eaaa1f7 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -167,16 +167,18 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 
 	acpi=		[HW,ACPI,X86,ARM64]
 			Advanced Configuration and Power Interface
-			Format: { force | off | strict | noirq | rsdt |
+			Format: { force | on | off | strict | noirq | rsdt |
 				  copy_dsdt }
 			force -- enable ACPI if default was off
+			on -- enable ACPI but allow fallback to DT [arm64]
 			off -- disable ACPI if default was on
 			noirq -- do not use ACPI for IRQ routing
 			strict -- Be less tolerant of platforms that are not
 				strictly ACPI specification compliant.
 			rsdt -- prefer RSDT over (default) XSDT
 			copy_dsdt -- copy DSDT to memory
-			For ARM64, ONLY "acpi=off" or "acpi=force" are available
+			For ARM64, ONLY "acpi=off", "acpi=on" or "acpi=force"
+			are available
 
 			See also Documentation/power/runtime_pm.txt, pci=noacpi
 
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index 6884c7678453170f0da0cab583794072c9f34443..3e4f1a45b125f61821ca579f4c7569d1977de99d 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -42,6 +42,7 @@ int acpi_pci_disabled = 1;	/* skip ACPI PCI scan and IRQ initialization */
 EXPORT_SYMBOL(acpi_pci_disabled);
 
 static bool param_acpi_off __initdata;
+static bool param_acpi_on __initdata;
 static bool param_acpi_force __initdata;
 
 static int __init parse_acpi(char *arg)
@@ -52,6 +53,8 @@ static int __init parse_acpi(char *arg)
 	/* "acpi=off" disables both ACPI table parsing and interpreter */
 	if (strcmp(arg, "off") == 0)
 		param_acpi_off = true;
+	else if (strcmp(arg, "on") == 0) /* prefer ACPI over DT */
+		param_acpi_on = true;
 	else if (strcmp(arg, "force") == 0) /* force ACPI to be enabled */
 		param_acpi_force = true;
 	else
@@ -198,10 +201,11 @@ void __init acpi_boot_table_init(void)
 	 * - ACPI has been disabled explicitly (acpi=off), or
 	 * - the device tree is not empty (it has more than just a /chosen node,
 	 *   and a /hypervisor node when running on Xen)
-	 *   and ACPI has not been force enabled (acpi=force)
+	 *   and ACPI has not been [force] enabled (acpi=on|force)
 	 */
 	if (param_acpi_off ||
-	    (!param_acpi_force && of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
+	    (!param_acpi_on && !param_acpi_force &&
+	     of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
 		return;
 
 	/*