From mboxrd@z Thu Jan 1 00:00:00 1970 From: pavel@ucw.cz (Pavel Machek) Date: Thu, 3 Nov 2016 10:57:58 +0100 Subject: how to enable suspend to ram for arm-64 bits In-Reply-To: <20161019131145.GA11036@leverpostej> References: <06a4f0d7-9022-578d-99e0-ddcde31ed895@arm.com> <82ddd0e1-9ecc-5e54-e8ee-86f947fc0ecd@arm.com> <20161018100002.GA4347@xo-6d-61-c0.localdomain> <20161018104539.GB15639@leverpostej> <20161019094227.GB1461@amd> <20161019131145.GA11036@leverpostej> Message-ID: <20161103095758.GA7973@amd> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed 2016-10-19 14:11:45, Mark Rutland wrote: > On Wed, Oct 19, 2016 at 11:42:27AM +0200, Pavel Machek wrote: > > On Tue 2016-10-18 11:45:39, Mark Rutland wrote: > > > Either the lowlevel suspend code is stable and bug free, and then > > having that code is not a problem. > > This ignores the cost of maintaining that code. Kernel APIs change over > time, and no code is ever completely stable, even if at one point in > time it happens to be bug-free. Well, kernel interfaces only change when there's good reason for a change, and if you force stable binary interface to external component, and there _is_ need for a change, we are all screwed. > > BSD is better than closed source, but it also means that you will not > > get the sources from your hw vendor. > > That depends on your hardware vendor, as always. There are a number of > platform ports in the upstream ATF repo. > > It's also worth considering that a number of 32-bit arm parts require > closed firmware (as far as I can tell, including the N900). Yeah, but we are trying to remove closed firmware. Don't make people add more of it... > > Being separate module means it will be hard to debug, in area where > > debugging is already pretty hard. > > It can be harder, yes. There are also benefits, given the same code can > be tested on a variety of platforms. What benefits? You are able to share code between platforms in kernel, too. > > Can it do advanced stuff like deep powersaving on N900 idle? > > Sorry, I don't know precisely what you're referring to. > > It can do things like shutting down entire CPU clusters (and IIRC > associated interconnect) when all relevant CPUs are idle, if that's what > you mean. I mean equivalent power savings between idle system and system in s2ram. Best regards, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 181 bytes Desc: Digital signature URL: