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. > > Now, As I understand thus far, I have the following options ( > requirement 3 above I will ignore, don't know how to handle it yet, > and assume for meanwhile that I have sysfs) : > 1. use suspend scheme (no runtime PM) > 1.a. create some kernel thread who check cpu load and will decide > to disable system only if its below some minimum threshold (which > should indicate no activity) > 1.b. initialize all HW interrupts (gpio, uart, etc) as wakeup sources > with this scheme only this thread is responsible for the suspend, > and there is no use of the runtime PM, right ? > > 2. use runtime PM scheme : > With this scheme I don't understand how some device will wake the > system , or doesn't it need to ? If a driver wakes up maybe it need > to deliver some info to system ? > > I think option 1 is also easier to support, what do you think about both ? > > Thanks!! > Ran Does Anyone have any suggestions and feedback on the above requirements ? Thank you, Ran _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
