Re: API for querying the resume cause
From: Yan Pashkovsky <hidden>
Date: 2015-08-20 21:44:47
Hi, I have subscribed to linux-pm@lists.linux-foundation.org and Majordomo@vger.kernel.org (linux-pm). I've written you earlier, hope you received my message. I haven't received any replies, so I send this message again, cause I think my message was declined. 20.08.2015 14:47, Yan wrote you: > Dear developers, > > My name is Yan and I was redirected here from kernel bugzilla > (bugzilla.kernel.org/show_bug.cgi?id=102991). I would like to discuss > API for supporting delayed hibernation. > > Original post: > > Please add API for querying the resume cause > The purpose of this API - is support of delayed hibernation (feature > that works for a long time in Windows). A laptop first Suspend to > RAM, then after a time save state to disk and power off completely. > But system must know the reason of waking up (was it user or turning > into hibernation). RTC wakeup event isn't reliable. > SystemD needs such API, see more at > github.com/systemd/systemd/issues/926 > > > I was discussing it earlier with Lennart Poettering, he said he can't > rely on rtc timer, he needs some API. > Lennart(github.com/systemd/systemd/issues/926): > > On Linux we have no API for querying the resume cause. Patching > around this sounds like a gigantic hack... Especially as RTC-based > wakeups are not really reliable on many systems... On such systems > where the RTC wakeup is missed and the user resumes the machine > manually later on the system will immediately go to hiberantion, > which is clearly not a good idea. > > Sorry, but I am really not convinced this could be any more than a > gigantic hack. > > Please before looking into something like this, let's at least get a > proper API into the kernel that reports the precise wakeup reason to > userspace. If we have that, then we can consider hooking this up > from userspace. Will close this for now, as I don't think we should > hack something up like this without proper kernel support for such a > logic. > > > PS I use mailing list system for the first time. Am I to subscribe to it > somewhere? Will feedback be delivered to my email address after sending > this email, without any actions? > > King regards, > Yan