From db96a75946d3a2a41092c83992e65f727cd35529 Mon Sep 17 00:00:00 2001 From: Chen Yu Date: Thu, 2 Apr 2020 15:56:52 +0800 Subject: [PATCH] PM: sleep: Add pm_debug_messages kernel command line option Debug messages from the system suspend/hibernation infrastructure are 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, for example. Add a kernel command line option to set pm_debug_messages during boot up. Signed-off-by: Chen Yu [ rjw: Subject & changelog ] Signed-off-by: Rafael J. Wysocki --- 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 4e3885e38179..df2c2b97f417 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3719,6 +3719,9 @@ Override pmtimer IOPort with a hex value. e.g. pmtmr=0x508 + pm_debug_messages [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..40f86ec4ab30 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_messages_setup(char *str) +{ + pm_debug_messages_on = true; + return 1; +} +__setup("pm_debug_messages", pm_debug_messages_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.