From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Mark Salter <msalter@redhat.com>
Date: Fri, 11 May 2018 21:01:17 -0400
Subject: [PATCH] acpi: prefer booting with ACPI over DTS

Message-id: <20180511210117.10457-1-msalter@redhat.com>
Patchwork-id: 214708
O-Subject: [RHEL-8 BZ1576869] [RHEL only] acpi: prefer booting with ACPI over DTS
Bugzilla: 1576869
RH-Acked-by: Jonathan Toppins <jtoppins@redhat.com>
RH-Acked-by: Tony Camuso <tcamuso@redhat.com>
RH-Acked-by: Bhupesh Sharma <bhsharma@redhat.com>
RH-Acked-by: Dean Nelson <dnelson@redhat.com>

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1576869
Brew: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=16208479
Testing: Verified kernel defaults to ACPI on Mustang

From: Jonathan Toppins <jtoppins@redhat.com>

    This patch forces ACPI boot tables to be preferred over DTS.

    Currently for ACPI to be used a user either has to set acpi=on on the
    kernel command line or make sure any device tree passed to the kernel
    is empty. If the dtb passed to the kernel is non-empty then device-tree
    will be chosen as the boot method of choice.

    RHEL does not wish to support this boot method so change table boot
    preferences to use ACPI. In the event ACPI table checks fail the kernel
    will fallback to using DTS to boot.

    Signed-off-by: Jonathan Toppins <jtoppins@redhat.com>

Upstream Status: RHEL only
Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Herton R. Krzesinski <herton@redhat.com>
---
 arch/arm64/kernel/acpi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index a85174d05473..2e4ba374ab54 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -40,7 +40,7 @@ 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_on __initdata = true;
 static bool param_acpi_force __initdata;

 static int __init parse_acpi(char *arg)
-- 
2.26.2

