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authorBrian Norris <computersforpeace@gmail.com>2015-02-23 06:16:49 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-02-26 01:21:26 +0100
commit1d4a9c17d4d204a159139361e8d4db7f9f267879 (patch)
treea419a5a715a3506e7972b556591b252f3b6ee10b /kernel/power
parentLinux 4.0-rc1 (diff)
downloadlinux-1d4a9c17d4d204a159139361e8d4db7f9f267879.tar.xz
linux-1d4a9c17d4d204a159139361e8d4db7f9f267879.zip
PM / sleep: add configurable delay for pm_test
When CONFIG_PM_DEBUG=y, we provide a sysfs file (/sys/power/pm_test) for selecting one of a few suspend test modes, where rather than entering a full suspend state, the kernel will perform some subset of suspend steps, wait 5 seconds, and then resume back to normal operation. This mode is useful for (among other things) observing the state of the system just before entering a sleep mode, for debugging or analysis purposes. However, a constant 5 second wait is not sufficient for some sorts of analysis; for example, on an SoC, one might want to use external tools to probe the power states of various on-chip controllers or clocks. This patch turns this 5 second delay into a configurable module parameter, so users can determine how long to wait in this pseudo-suspend state before resuming the system. Example (wait 30 seconds); # echo 30 > /sys/module/suspend/parameters/pm_test_delay # echo core > /sys/power/pm_test # time echo mem > /sys/power/state ... [ 17.583625] suspend debug: Waiting for 30 second(s). ... real 0m30.381s user 0m0.017s sys 0m0.080s Signed-off-by: Brian Norris <computersforpeace@gmail.com> Acked-by: Pavel Machek <pavel@ucw.cz> Reviewed-by: Kevin Cernekee <cernekee@chromium.org> Acked-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'kernel/power')
-rw-r--r--kernel/power/suspend.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index b7d6b3a721b1..8d7a1ef72758 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -28,6 +28,7 @@
#include <linux/ftrace.h>
#include <trace/events/power.h>
#include <linux/compiler.h>
+#include <linux/moduleparam.h>
#include "power.h"
@@ -233,12 +234,20 @@ static bool platform_suspend_again(suspend_state_t state)
suspend_ops->suspend_again() : false;
}
+#ifdef CONFIG_PM_DEBUG
+static unsigned int pm_test_delay = 5;
+module_param(pm_test_delay, uint, 0644);
+MODULE_PARM_DESC(pm_test_delay,
+ "Number of seconds to wait before resuming from suspend test");
+#endif
+
static int suspend_test(int level)
{
#ifdef CONFIG_PM_DEBUG
if (pm_test_level == level) {
- printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
- mdelay(5000);
+ printk(KERN_INFO "suspend debug: Waiting for %d second(s).\n",
+ pm_test_delay);
+ mdelay(pm_test_delay * 1000);
return 1;
}
#endif /* !CONFIG_PM_DEBUG */