Debug messages from the system suspend/hibernation infrastructure
is disabled by default, and can only be enabled after the system
has boot up via /sys/power/pm_debug_messages. This makes the hibernation
resume hard to track as it involves system boot up across hibernation.
There's no chance for software_resume() to track the resume process,
eg.
Turning on the pm_debug_messages during boot up by appending
'pm_debug_message'.
Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Signed-off-by: Chen Yu <yu.c.chen@xxxxxxxxx>
---
v2: According to Randy's suggestion, add the command line
option to Documentation/admin-guide/kernel-parameters.txt
---
Documentation/admin-guide/kernel-parameters.txt | 3 +++
kernel/power/main.c | 7 +++++++
2 files changed, 10 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index c07815d230bc..105ec73743d7 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3698,6 +3698,9 @@
Override pmtimer IOPort with a hex value.
e.g. pmtmr=0x508
+ pm_debug_message [SUSPEND,KNL]
+ Enable suspend/resume debug messages during boot up.
+
pnp.debug=1 [PNP]
Enable PNP debug messages (depends on the
CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 69b7a8aeca3b..1da3d7c15e03 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -535,6 +535,13 @@ static ssize_t pm_debug_messages_store(struct kobject *kobj,
power_attr(pm_debug_messages);
+static int __init pm_debug_message_setup(char *str)
+{
+ pm_debug_messages_on = true;
+ return 1;
+}
+__setup("pm_debug_message", pm_debug_message_setup);
+
/**
* __pm_pr_dbg - Print a suspend debug message to the kernel log.
* @defer: Whether or not to use printk_deferred() to print the message.
--
2.17.1
