On Tue, May 5, 2015 at 12:35 PM, Alan Stern <st...@rowland.harvard.edu> wrote: > On Tue, 5 May 2015, Chirantan Ekbote wrote: > >> This is our plan for the next version (see my email earlier in this >> thread). Keeping a hybrid power state with hacks in the drivers isn't >> really maintainable, scalable, or upstream-able and has caused us some >> headaches already. Unfortunately we were working with the 3.14 kernel >> at the time, which didn't have the framework necessary to do anything >> else. The new version of lucid sleep will have the power manager >> runtime suspend power-hungry devices before a suspend so that they >> remain powered off at resume time. The power manager can then decide >> to resume those devices based on whether the wakeup event was >> user-triggered. >> >> Being able to determine the wakeup type from userspace is the only >> functionality we need from the kernel that doesn't already exist in >> mainline. > > Maybe you can simplify the problem. You don't really need to know the > wakeup type, or to determine which device was responsible for the > wakeup. All you really need to know is whether the wakeup was > user-triggered. That may be much easier to discover. >
You are, of course, correct. Ultimately the only requirement we have is that there exists a way for userspace to determine if the system woke up because of a user-triggered event. The actual mechanism by which this determination is made isn't something I feel strongly about. The reason I had been focusing on exposing the actual wakeup event to userspace is because classifying wakeup events as user-triggered or not feels to me like a policy decision that should be left to userspace. If the kernel maintainers are ok with doing this work in the kernel instead and only exposing a binary yes/no bit to userspace for user-triggered wakeups, that's perfectly fine because it still meets our requirements. > Alan Stern > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
