From 1d4a9c17d4d204a159139361e8d4db7f9f267879 Mon Sep 17 00:00:00 2001 From: Brian Norris Date: Sun, 22 Feb 2015 21:16:49 -0800 Subject: [PATCH] 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 Acked-by: Pavel Machek Reviewed-by: Kevin Cernekee Acked-by: Florian Fainelli Signed-off-by: Rafael J. Wysocki --- Documentation/kernel-parameters.txt | 7 +++++++ Documentation/power/basic-pm-debugging.txt | 10 ++++++---- kernel/power/suspend.c | 13 +++++++++++-- 3 files changed, 24 insertions(+), 6 deletions(-) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index bfcb1a62a7b4..8b1fa5e129ac 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -3462,6 +3462,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. improve throughput, but will also increase the amount of memory reserved for use by the client. + suspend.pm_test_delay= + [SUSPEND] + Sets the number of seconds to remain in a suspend test + mode before resuming the system (see + /sys/power/pm_test). Only available when CONFIG_PM_DEBUG + is set. Default value is 5. + swapaccount=[0|1] [KNL] Enable accounting of swap in memory resource controller if no parameter or 1 is given or disable diff --git a/Documentation/power/basic-pm-debugging.txt b/Documentation/power/basic-pm-debugging.txt index edeecd447d23..b96098ccfe69 100644 --- a/Documentation/power/basic-pm-debugging.txt +++ b/Documentation/power/basic-pm-debugging.txt @@ -75,12 +75,14 @@ you should do the following: # echo platform > /sys/power/disk # echo disk > /sys/power/state -Then, the kernel will try to freeze processes, suspend devices, wait 5 seconds, -resume devices and thaw processes. If "platform" is written to +Then, the kernel will try to freeze processes, suspend devices, wait a few +seconds (5 by default, but configurable by the suspend.pm_test_delay module +parameter), resume devices and thaw processes. If "platform" is written to /sys/power/pm_test , then after suspending devices the kernel will additionally invoke the global control methods (eg. ACPI global control methods) used to -prepare the platform firmware for hibernation. Next, it will wait 5 seconds and -invoke the platform (eg. ACPI) global methods used to cancel hibernation etc. +prepare the platform firmware for hibernation. Next, it will wait a +configurable number of seconds and invoke the platform (eg. ACPI) global +methods used to cancel hibernation etc. Writing "none" to /sys/power/pm_test causes the kernel to switch to the normal hibernation/suspend operations. Also, when open for reading, /sys/power/pm_test 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 #include #include +#include #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 */ -- 2.39.5