linux/Documentation/power
ShuoX Liu 2a77c46de1 PM / Suspend: Add statistics debugfs file for suspend to RAM
Record S3 failure time about each reason and the latest two failed
devices' names in S3 progress.
We can check it through 'suspend_stats' entry in debugfs.

The motivation of the patch:

We are enabling power features on Medfield. Comparing with PC/notebook,
a mobile enters/exits suspend-2-ram (we call it s3 on Medfield) far
more frequently. If it can't enter suspend-2-ram in time, the power
might be used up soon.

We often find sometimes, a device suspend fails. Then, system retries
s3 over and over again. As display is off, testers and developers
don't know what happens.

Some testers and developers complain they don't know if system
tries suspend-2-ram, and what device fails to suspend. They need
such info for a quick check. The patch adds suspend_stats under
debugfs for users to check suspend to RAM statistics quickly.

If not using this patch, we have other methods to get info about
what device fails. One is to turn on  CONFIG_PM_DEBUG, but users
would get too much info and testers need recompile the system.

In addition, dynamic debug is another good tool to dump debug info.
But it still doesn't match our utilization scenario closely.
1) user need write a user space parser to process the syslog output;
2) Our testing scenario is we leave the mobile for at least hours.
   Then, check its status. No serial console available during the
   testing. One is because console would be suspended, and the other
   is serial console connecting with spi or HSU devices would consume
   power. These devices are powered off at suspend-2-ram.

Signed-off-by: ShuoX Liu <shuox.liu@intel.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-10-16 23:27:45 +02:00
..
regulator regulator: Remove supply_regulator_dev from machine configuration 2011-05-27 10:34:37 +01:00
00-INDEX PM: Introduce library for device-specific OPPs (v7) 2010-10-17 01:57:50 +02:00
apm-acpi.txt Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00
basic-pm-debugging.txt PM / Suspend: Add statistics debugfs file for suspend to RAM 2011-10-16 23:27:45 +02:00
devices.txt PM / Runtime: Update documentation of interactions with system sleep 2011-07-02 14:30:09 +02:00
drivers-testing.txt PM: Fix references to basic-pm-debugging.txt in drivers-testing.txt 2010-12-24 15:02:41 +01:00
freezing-of-tasks.txt freezer: do not send signals to kernel threads 2007-10-18 14:37:19 -07:00
interface.txt PM / Hibernate: Make default image size depend on total RAM size 2010-10-17 01:57:43 +02:00
notifiers.txt PM: Allow drivers to allocate memory from .prepare() callbacks safely 2011-05-17 23:26:00 +02:00
opp.txt PM / OPP: Introduce function to free cpufreq table 2011-07-15 23:58:18 +02:00
pci.txt PM/PCI: Update PCI power management documentation 2010-05-18 15:01:58 -07:00
pm_qos_interface.txt PM / QoS: Update Documentation for the pm_qos and dev_pm_qos frameworks 2011-10-04 21:54:45 +02:00
power_supply_class.txt power_supply: Add a charge_type property, and use it for olpc driver 2009-07-02 18:14:37 +04:00
runtime_pm.txt Merge branch 'pm-runtime' into pm-for-linus 2011-10-16 23:26:49 +02:00
s2ram.txt PM: Add sysfs attr for rechecking dev hash from PM trace 2010-10-17 01:57:50 +02:00
states.txt PM: Documentation/power/states.txt: fix repetition 2011-03-15 00:43:17 +01:00
swsusp-and-swap-files.txt typo fixes 2007-10-20 01:34:40 +02:00
swsusp-dmcrypt.txt [PATCH] swsusup with dm-crypt mini howto 2005-09-05 00:06:17 -07:00
swsusp.txt Fix common misspellings 2011-03-31 11:26:23 -03:00
tricks.txt update email address 2010-07-19 10:56:54 +02:00
userland-swsusp.txt Fix common misspellings 2011-03-31 11:26:23 -03:00
video_extension.txt [PATCH] acpi: fix video docs 2005-06-25 16:24:32 -07:00
video.txt Documentation: update broken web addresses. 2010-08-04 15:21:40 +02:00