From b187c14ada3065c0b317c70cc97f27035edd0bc8 Mon Sep 17 00:00:00 2001
From: Igor Druzhinin <igor.druzhinin@citrix.com>
Date: Thu, 5 Mar 2020 11:32:24 +0100
Subject: [PATCH] x86/suspend: disable watchdog before calling
 console_start_sync()

... and enable it after exiting S-state. Otherwise accumulated
output in serial buffer might easily trigger the watchdog if it's
still enabled after entering sync transmission mode.

The issue observed on machines which, unfortunately, generate non-0
output in CPU offline callbacks.

Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 5e08f5f56c9955d853c26c985b6fb1fb45d0355d
master date: 2020-01-29 15:06:10 +0100
---
 xen/arch/x86/acpi/power.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/xen/arch/x86/acpi/power.c b/xen/arch/x86/acpi/power.c
index a704c7c340..4c12794809 100644
--- a/xen/arch/x86/acpi/power.c
+++ b/xen/arch/x86/acpi/power.c
@@ -23,6 +23,7 @@
 #include <xen/domain.h>
 #include <xen/console.h>
 #include <xen/iommu.h>
+#include <xen/watchdog.h>
 #include <xen/cpu.h>
 #include <public/platform.h>
 #include <asm/tboot.h>
@@ -194,6 +195,7 @@ static int enter_state(u32 state)
 
     acpi_sleep_prepare(state);
 
+    watchdog_disable();
     console_start_sync();
     printk("Entering ACPI S%d state.\n", state);
 
@@ -206,6 +208,7 @@ static int enter_state(u32 state)
         system_state = SYS_STATE_resume;
         device_power_up(error);
         console_end_sync();
+        watchdog_enable();
         error = -EIO;
         goto done;
     }
@@ -252,6 +255,7 @@ static int enter_state(u32 state)
         tboot_s3_error(error);
 
     console_end_sync();
+    watchdog_enable();
 
     microcode_resume_cpu(0);
 
-- 
2.30.2