On Wed, Sep 17, 2014 at 11:16 AM, Peter Teoh <htmldeveloper@xxxxxxxxx> wrote:
On Sun, Sep 14, 2014 at 2:11 AM, Ran Shalit <ranshalit@xxxxxxxxx> wrote:On Thu, Sep 11, 2014 at 12:24 PM, Ran Shalit <ranshalit@xxxxxxxxx> wrote:
> On Thu, Sep 11, 2014 at 8:32 AM, AYAN KUMAR HALDER <ayankumarh@xxxxxxxxx> wrote:
>> On Thu, Sep 11, 2014 at 12:55 AM, <Valdis.Kletnieks@xxxxxx> wrote:
>>> On Wed, 10 Sep 2014 21:58:48 +0300, Ran Shalit said:
>>>
>>>> 1. How can I make a process to notice this inactivity ? Do you think
>>>> it can be implemented by some periodic process who check if there is
>>>> activity ? It returns to the original question I raised, that I will
>>>> use some periodic process who checks maybe cpu load or something like
>>>> that. What do you think ?
>>>
>>> That's going to depend on your system and what processes are running.
>>>
>>> You may have an MP3 player going that doesn't take much CPU at all - but
>>> shutting down because the user hasn't hit a button in 47 minutes will probably
>>> irritate the user no end. Or there may be a screensaver running that takes
>>> twice as much CPU as the MP3 player, but is totally OK on the system
>>> suspending whenever the rest of the system wants it.
>>>
>>> You're going to have to look at your system design, and decide for yourself
>>> what the criteria are.
>>
>> Please correct me if my understanding is wrong:-
>>
>> I believe that autosuspend feature (for system suspend) is not present
>> in kernel. I believe that there is no feature in kernel which checks
>> for system ( cpu, devices) inactivity and suspends the entire system.
>> System suspend is caused when :-
>> 1. the user issues a command
>> 2. The system receives some interrupt or event (lid closing event)
>> 3. There is an external process which monitors system inactivity and
>> suspends the system.
>>
>> For runtime suspend of a device, I believe it is the driver who has
>> the complete responsibility to decide when to suspend the device or
>> resume it. The driver can take this decision on user intervention (eg
>> when user writes to /sys/devices/<my-device>/power/* ) or when the
>> driver has completed servicing an interrupt and feels it has nothing
>> more to do, etc
>
> Thanks Vlaid, Ayan,
>
> I am a bit yet struggling for couple of days on this PM issue, and I
> would appreciate your continous advise.
> The system requirement I have is as following:
> 1. make everything as automatic as possible , so that there won't be
> any need to add any userspace application for the matter.
> 2. wakeup from all relevant wakeup sources
> 3. should not use sysfs (it should be disabled from kernel)
> 4. platform is OMAP3530.
a. look into /arch/arm/mach-omap2 of kernel source and grep for "sleep" and "wakeup" functionality: power management is just managing with the different frequencies of the the CPU. as far as I can tell, once sleep, only uart pin can be used for waking up....not sure.b. read this:http://www.ti.com/lit/an/slva310b/slva310b.pdf (read page 2, which describe the different powerup-sequence of the CPU, "Powering-Up Sequence".c. the technology brand name for omap3530 is "DVFS"....search for this inside the arch/arm kernel source.....you can find lots of sample codes there.(don't confuse with another omap CPU brand name "DeepSleep" but is PM for another type of omap cpu.)d. http://www.ti.com/product/omap3530 --> on the right is a DVSDK + Android source code for 3530....grep the codes for the above keywords...hopefully it helps?
at the risk of missing out other files:
how about this two files:
inside arch/arm/mach-omap2:
omap-pm.h
omap-pm-noop.c
inside arch/arm/mach-omap2:
omap-pm.h
omap-pm-noop.c
which I think provide a lot of hint for you.
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