[PATCH] arm64: efi: add check for broken efi poweroff

[Shawn Guo <shawn.guo@xxxxxxxxxx>]

Poweroff via UEFI Runtime Services doesn't always work on every single
arm64 machine.  For example, on Lenovo Flex 5G laptop, it results in
a system reboot rather than shutdown.  Add a DMI check to keep such
system stay with the original poweroff method (PSCI).

Signed-off-by: Shawn Guo <shawn.guo@xxxxxxxxxx>
---
 arch/arm64/kernel/efi.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index fa02efb28e88..8ae0002c72f1 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -7,6 +7,7 @@
  * Copyright (C) 2013, 2014 Linaro Ltd.
  */
 
+#include <linux/dmi.h>
 #include <linux/efi.h>
 #include <linux/init.h>
 
@@ -113,12 +114,26 @@ int __init efi_set_mapping_permissions(struct mm_struct *mm,
 				   set_permissions, md);
 }
 
+static const struct dmi_system_id efi_reboot_broken_table[] = {
+	{
+		.ident = "Lenovo Flex 5G",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "Flex 5G"),
+		},
+	},
+	{ } /* terminator */
+};
+
 /*
  * UpdateCapsule() depends on the system being shutdown via
  * ResetSystem().
  */
 bool efi_poweroff_required(void)
 {
+	if (dmi_check_system(efi_reboot_broken_table))
+		return false;
+
 	return efi_enabled(EFI_RUNTIME_SERVICES);
 }
 
-- 
2.17.1