Two parts here, first part is for Frank, second is for the original
post (inline).
Applications:
Once all apps have released their wakelocks
App Framework:
Power manager service decides to suspend the device (if the user turns
off the screen)
by writing "mem" to /sys/power/state
Kernel:
early suspend hooks get called, entry point is:
kerne/power/main.c: state_store()....
196 #ifdef CONFIG_SUSPEND
197 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
198 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
199 break;
200 }
201 if (state < PM_SUSPEND_MAX && *s)
202 #ifdef CONFIG_EARLYSUSPEND
203 if (state == PM_SUSPEND_ON || valid_state(state)) {
204 error = 0;
205 request_suspend_state(state);
// Early suspend here (screen off is triggered here)
206 }
207 #else
208 error = enter_state(state);
// Regular linux suspend occurs here
209 #endif
210 #endif
The order which events occurs is the following:
early suspend (triggered by pressing power button to turn screen off)
normal supsend hooks (triggered by last wakelock released from the kernel)
cpu sleep
normal resume
late resume (triggers by pressing power button to turn screen on)
If you want to debug suspend, theres a few things you can do.
enable CONFIG_PM_DEBUG and PM_VERBOSE, which combined will print out
to the dmesg when each driver suspends and resumes
There is also:
/sys/module/wakelock/parameters/debug_mask
/sys/module/earlysuspend/parameters/debug_mask
you can see the debug mask flags here:
http://android.git.kernel.org/?p=kernel/common.git;a=blob;f=kernel/power/earlysuspend.c;h=84bed51dcdce79503d718186775e690560d4637b;hb=android-2.6.32
and
http://android.git.kernel.org/?p=kernel/common.git;a=blob;f=kernel/power/wakelock.c;h=ca48bb8d316b9cfc0bf6db0c0a2c6667ceb44699;hb=android-2.6.32
-- Mike
On Tue, Jun 15, 2010 at 8:46 AM, frank.sposaro <frank.spos...@gmail.com> wrote:
> Hi Raj.
>
> Any luck on this?
> I am trying to trace the full process of how things get shut down when
> the phone is suspended.
> Where I am at right now is that when the phone is suspended or resumed
> the earlysuspend.c
> file executes a function and places a earlysuspend struct on a
> work_queue.
> I'm trying to find the specific android power management that get's
> applied over top of the linux PM. (see graph in link below)
> Feeling like that graph may be slightly out of date and things moved
> around, but I may be missing something.
> I wish those writing Android Docs would time stamp everything.
>
>
> Power
>
> http://source.android.com/porting/power_management.html
> ----- Attempting to trace the tree above ----
>
> PowerManager
> http://developer.android.com/reference/android/os/PowerManager.html
>
> PowerManagerService.java
> http://android.git.kernel.org/?p=platform/frameworks/base.git;a=blob;f=services/java/com/android/server/PowerManagerService.java;h=966ecb0bf5e34c61c54a73b22ade873b7e564b23;hb=HEAD
>
> * Not finding /lib/hardware/power.c or /drivers/android/power.c *
>
> spos...@mobiprog:~/android-source/donut$ find . power.c | grep power.c
> ./hardware/libhardware_legacy/power/power.c
> ./msm/arch/mips/au1000/common/power.c
> ./msm/arch/powerpc/platforms/pseries/power.c
> ./msm/arch/sparc64/kernel/power.c
> ./msm/drivers/acpi/power.c ---- Mabey this? ACPI Bus Power
> Management, but doesn't look Android Specific. 2002. See link below
> ./msm/drivers/parisc/power.c -- HP PARISC soft power switch
> support drive
> ./msm/drivers/power/apm_power.c
> ./msm/drivers/power/pda_power.c
> ./msm/drivers/input/apm-power.c
> ./msm/drivers/net/wireless/iwlwifi/iwl-power.c
>
>
> /*
> * acpi_power.c - ACPI Bus Power Management
> * ACPI power-managed devices may be controlled in two ways:
> * 1. via "Device Specific (D-State) Control"
> * 2. via "Power Resource Control".
> * This module is used to manage devices relying on Power Resource
> Control.
> *
> * An ACPI "power resource object" describes a software controllable
> power
> * plane, clock plane, or other resource used by a power managed
> device.
> * A device may rely on multiple power resources, and a power resource
> * may be shared by multiple devices.
> */
> http://android.git.kernel.org/?p=kernel/msm.git;a=blob;f=drivers/acpi/power.c;h=c926e7d4a0d619fd5b16a3b8d4806b05bba5aeeb;hb=android-msm-2.6.29-donut
>
>
> ---- Additional NDK Files. These are Android Specific, but on top of
> the kernel ----
>
> com_android_server_BatteryService.cpp
> http://android.git.kernel.org/?p=platform/frameworks/base.git;a=blob;f=services/jni/com_android_server_BatteryService.cpp;h=8e7cadc6b680fc420d341faa094c71922946fdab;hb=HEAD
>
> com_android_server_HardwareService.cpp
> http://android.git.kernel.org/?p=platform/frameworks/base.git;a=blob;f=services/jni/com_android_server_HardwareService.cpp;h=253e6558de36f943dc324415a9c41e6eb23cd308;hb=HEAD
>
>
> GlobalActions.java was PowerDialog.java
> http://android.git.kernel.org/?p=platform/frameworks/policies/base.git;a=blob;f=mid/com/android/internal/policy/impl/GlobalActions.java;h=c7d4b14bb7def6d47f32bc5efaacd91056d51be1;hb=HEAD
>
> Sleep and wake up as shown in dmesg
> <6>[16337.332275] request_suspend_state: wakeup (3->0) at
> 16331561233285 (2010-06-15 01:00:37.811553944 UTC)
> <4>[16337.527679] init sharp panel
> <6>[16343.192291] request_suspend_state: sleep (0->3) at
> 16337421218656 (2010-06-15 01:00:43.671569832 UTC)
> <4>[16343.234863] deinit sharp panel
>
> /*
> * prints "request_suspend_state" above
> * all is seems to do is create an earlysuspend struct
> * and place it on the work_queue
> */
> earlysuspend.c
> http://android.git.kernel.org/?p=kernel/msm.git;a=blob;f=kernel/power/earlysuspend.c;h=84bed51dcdce79503d718186775e690560d4637b;hb=HEAD
>
>
> /* The early_suspend structure defines suspend and resume hooks to be
> called
> * when the user visible sleep state of the system changes, and a
> level to
> * control the order. They can be used to turn off the screen and
> input
> * devices that are not used for wakeup.
> * Suspend handlers are called in low to high level order, resume
> handlers are
> * called in the opposite order. If, when calling
> register_early_suspend,
> * the suspend handlers have already been called without a matching
> call to the
> * resume handlers, the suspend handler will be called directly from
> * register_early_suspend. This direct call can violate the normal
> level order.
> */
> earlysuspend.h
> http://randomtechinfo.com/sdx/include/earlysuspend.h
>
> power.h
> http://android.git.kernel.org/?p=kernel/msm.git;a=blob;f=kernel/power/power.h;h=96cab35c3d22a3f1e337c141439c768dc4e4f4b3;hb=HEAD
>
>
>
>
>
> On Jun 1, 7:33 am, Raj Kumar <rajkumar...@gmail.com> wrote:
>> Hi all,
>>
>> I have question regardingpowermanagement in kernel. What APIs are
>> available in linux kernel
>> forpowermanagement are available for device drivers? e.g. Driver is
>> interested in knowing the systempowerstartes. Which APIs the driver should
>> register for which it will
>> get notifications ofpowerstates
>> in system?
>>
>> Previously in linux kernel pm_register was used which is obselete now.
>> There are other things as well
>> like APM and ACPI. But for embedded devices, if the driver is
>> interested in getting the systempower
>> states from kernel, which APIs are used?
>>
This is more linux PM specific not so much Android, but I don't mind
answering here, just for future reference in case you want a wider
audience.
You can the register_pm_notifier() call which will register a
notifier_block and you will receive events PM_SUSPEND_PREPARE,
PM_POST_SUSPEND etc.. Only a few drivers use this, I suggest you only
use this if you have a particular spot in suspend/resume that you need
to be called. Or your driver doesn't fit well in the device tree
More commonly is to use the struct dev_pm_ops and fill in your
.suspend_noirq .resume_noirq etc...
pm_ops seems to be the new way to suspend instead of just using the
suspend/resume calls in say struct platform_driver. Chances are your
driver's struct will have a struct pm_dev_ops in there somewhere that
you can fill out when you register.
Android has an extra early_suspend hook that gets called before all
linux-pm suspend hooks, which I explain above.
-- Mike
>> /r
>
> --
> unsubscribe: android-kernel+unsubscr...@googlegroups.com
> website: http://groups.google.com/group/android-kernel
>
--
unsubscribe: android-kernel+unsubscr...@googlegroups.com
website: http://groups.google.com/group/android-kernel
