From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH 1/1] suspend: delete sys_sync() Date: Mon, 06 Jul 2015 15:59:15 +0200 Message-ID: <4932758.cYVny4lmZN@vostro.rjw.lan> References: <2293886.L6VJGgjdDp@vostro.rjw.lan> <20150706110645.GC381@amd> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <20150706110645.GC381@amd> Sender: linux-kernel-owner@vger.kernel.org To: Pavel Machek Cc: Alan Stern , Dave Chinner , Len Brown , Henrique de Moraes Holschuh , One Thousand Gnomes , Linux PM list , "linux-kernel@vger.kernel.org" , Len Brown List-Id: linux-pm@vger.kernel.org On Monday, July 06, 2015 01:06:45 PM Pavel Machek wrote: > On Mon 2015-07-06 01:28:20, Rafael J. Wysocki wrote: > > On Saturday, July 04, 2015 10:19:55 AM Alan Stern wrote: > > > On Sat, 4 Jul 2015, Rafael J. Wysocki wrote: > > > > > > > The only argument against dropping sys_sync() from the suspend code path > > > > I've seen in this thread that I entirely agree with is that it may lead to > > > > regressions, because we've done it practically forever and it may hide latent > > > > bugs somewhere in block drivers etc. Dropping it, though, is the only way > > > > to see those bugs, if any, and if we want to ever fix them, we need to see > > > > them. That's why I think that it may be a good idea to allow people to > > > > drop it if they are willing to accept some extra risk (via the kernel > > > > command line, for example). > > > > > > I'd be perfectly happy to have the sync selectable at runtime, one way > > > or another. The three most reasonable options seem to be: > > > > > > kernel command line > > > > > > sysfs file > > > > > > sysctl setting > > > > > > The command line is less flexible (it can't be changed after booting). > > > Either of the other two would be fine with me. > > > > We'll probably use a sysfs file (possibly plus a Kconfig option to set the > > boot time default). > > Android people can already do sync-less s2ram using existing > interface. IMO they should just do it. > > In any case, sysfs file + Kconfig is an overkill. We already have too > many Kconfig options. I don't think we can reach a general agreement on what's the *right* approach with respect to the sys_sync() in the suspend code path, so the only way out of this situation I can see is to make it configurable. > There's not a single Android phone supported by mainline > kernel. I'm sure they have bigger problems than Android setting > default sysfs values... But perhaps we'd like to change that? Thanks, Rafael