From: tony@atomide.com (Tony Lindgren) Date: Fri, 5 Feb 2016 11:10:42 -0800 Subject: PM regression with commit 5de85b9d57ab PM runtime re-init in v4.5-rc1 In-Reply-To: References: <20160205010810.GR19432@atomide.com> Message-ID: <20160205191042.GT19432@atomide.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org * Ulf Hansson [160204 22:55]: > On 5 February 2016 at 02:08, Tony Lindgren wrote: > > * Ulf Hansson [160204 14:35]: > >> On 4 February 2016 at 23:09, Alan Stern wrote: > >> > On Thu, 4 Feb 2016, Ulf Hansson wrote: > >> > > >> >> I am really not questioning the autosuspend feature at all, it's a > >> >> really great feature! > >> >> > >> >> Now, I question the minor benefit we actually gain from having the > >> >> runtime PM core to update the mark in rpm_resume(). > >> > > >> > As Tony pointed out, it prevents some devices from going to sleep right > >> > away. > >> > >> Because their drivers don't care to update the last busy mark!? > > > > Nope. Without that devices may never resume at all so the drivers > > can't do anything about it. > > I don't get it. Why not? Because of another abuse of the runtime PM API? I think you should be able to test this case in your test driver by calling pm_runtime_resume() for your test driver after your test drive has autosuspended. Probably you need some delayed_work to do this in your test driver unless you have some test bus to go with it. > Or we should probably continue to focus on fixing the regression. :-) Naturally we should fix up things yeah :) Having a test driver that works on any architecture sure makes things easier to verify. Regards, Tony