From mboxrd@z Thu Jan 1 00:00:00 1970 From: rnayak@ti.com (Rajendra Nayak) Date: Mon, 31 Jan 2011 20:58:29 +0530 Subject: [linux-pm] [PATCH] i2c: OMAP: fix static suspend vs. runtime suspend In-Reply-To: References: <1a4ad626f3cb73267847e8ac7bd47545@mail.gmail.com> Message-ID: <266a2f0ec446d693cf9583681ca346e0@mail.gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org > -----Original Message----- > From: Alan Stern [mailto:stern at rowland.harvard.edu] > Sent: Monday, January 31, 2011 8:43 PM > To: Rajendra Nayak > Cc: Kevin Hilman; Ben Dooks; linux-i2c at vger.kernel.org; linux-pm at lists.linux-foundation.org; linux- > omap at vger.kernel.org; linux-arm-kernel at lists.infradead.org > Subject: Re: [linux-pm] [PATCH] i2c: OMAP: fix static suspend vs. runtime suspend > > On Mon, 31 Jan 2011, Rajendra Nayak wrote: > > > Can you elaborate a bit more on how/why runtime PM transitions > > are disabled during system suspend, and how is it taken care > > of that a runtime resume of a device works however a subsequent > > runtime (re)suspend does not? > > I'll answer for Kevin. This is done by the PM core, in order to > prevent runtime power transitions from interfering with a system power > transition. The PM core increments the device's usage_count; this > prevents the device from being runtime-suspended but it allows > runtime-resume calls to go through. Thanks, I did remember seeing the pm_runtime_get_noresume() in dpm_prepare(). Just did not correlate it was the same Kevin was trying to say. Regards, Rajendra > > Alan Stern