From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: how to enable suspend to ram for arm-64 bits Date: Thu, 3 Nov 2016 10:57:58 +0100 Message-ID: <20161103095758.GA7973@amd> 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> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="EeQfGwPcQSOJBaQU" Return-path: Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:54552 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753033AbcKCJ6B (ORCPT ); Thu, 3 Nov 2016 05:58:01 -0400 Content-Disposition: inline In-Reply-To: <20161019131145.GA11036@leverpostej> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Mark Rutland Cc: Sudeep Holla , yoma sophian , linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org --EeQfGwPcQSOJBaQU Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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: >=20 > > Either the lowlevel suspend code is stable and bug free, and then > > having that code is not a problem. >=20 > 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. >=20 > That depends on your hardware vendor, as always. There are a number of > platform ports in the upstream ATF repo. >=20 > 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. >=20 > 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? >=20 > Sorry, I don't know precisely what you're referring to. >=20 > 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 --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --EeQfGwPcQSOJBaQU Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlgbCiYACgkQMOfwapXb+vLsFgCguiSXLt6seNAL57Hxe8Pcgomp J4YAn08H6jICj8MtAn+vQNdlvpCc/T3t =PIH8 -----END PGP SIGNATURE----- --EeQfGwPcQSOJBaQU--