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 <[email protected]>
---
v2: - make this a module param instead of an explicit sysfs file
- drop the for loop; mdelay() does the same loop internally
- decrease +36 lines of code and +2 lines of doc, to +6 lines of code and
+2 lines of doc
kernel/power/suspend.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index c347e3ce3a55..aee23dab0a55 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"
@@ -204,12 +205,20 @@ 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 */
--
2.3.0
On Sun 2015-02-22 00:26:54, Brian Norris wrote:
> 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 <[email protected]>
Acked-by: Pavel Machek <[email protected]>
(Does this need documentation in kernel-parameters.txt or in place
where pm_test is documented?)
Thanks,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
On Sun, Feb 22, 2015 at 4:27 AM, Pavel Machek <[email protected]> wrote:
> On Sun 2015-02-22 00:26:54, Brian Norris wrote:
>> 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 <[email protected]>
>
> Acked-by: Pavel Machek <[email protected]>
>
> (Does this need documentation in kernel-parameters.txt or in place
> where pm_test is documented?)
Perhaps both places? Documentation/power/basic-pm-debugging.txt still
has the "wait 5 seconds" verbiage.
Beyond that, it looks good to me:
Reviewed-by: Kevin Cernekee <[email protected]>
Le 22/02/2015 00:26, Brian Norris a ?crit :
> 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 <[email protected]>
Acked-by: Florian Fainelli <[email protected]>
> ---
> v2: - make this a module param instead of an explicit sysfs file
> - drop the for loop; mdelay() does the same loop internally
> - decrease +36 lines of code and +2 lines of doc, to +6 lines of code and
> +2 lines of doc
>
> kernel/power/suspend.c | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
> index c347e3ce3a55..aee23dab0a55 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"
>
> @@ -204,12 +205,20 @@ 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 */
>
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 <[email protected]>
Acked-by: Pavel Machek <[email protected]>
Reviewed-by: Kevin Cernekee <[email protected]>
Acked-by: Florian Fainelli <[email protected]>
---
v3: - document in a few more places
v2: - make this a module param instead of an explicit sysfs file
- drop the for loop; mdelay() does the same loop internally
- decrease +36 lines of code and +2 lines of doc, to +6 lines of code and
+2 lines of doc
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 176d4fe4f076..0b8a1fd0d08d 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -3433,6 +3433,13 @@ 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 c347e3ce3a55..aee23dab0a55 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"
@@ -204,12 +205,20 @@ 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 */
--
2.3.0