From mboxrd@z Thu Jan 1 00:00:00 1970 From: boris.brezillon@free-electrons.com (Boris Brezillon) Date: Sat, 17 Jan 2015 10:36:09 +0100 Subject: [PATCH] USB: host: ehci_atmel: Add suspend/resume support In-Reply-To: <20150117013442.GV3843@piout.net> References: <1421437274-31615-1-git-send-email-sylvain.rochet@finsecur.com> <20150117013442.GV3843@piout.net> Message-ID: <20150117103609.276efecf@bbrezillon> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Sylvain, On Sat, 17 Jan 2015 02:34:42 +0100 Alexandre Belloni wrote: > Hi, > > You should probably put the susbsytem maintainers in copy too. As > reported by get_maintainer.pl: > Alan Stern (maintainer:USB EHCI DRIVER) > Greg Kroah-Hartman (supporter:USB SUBSYSTEM) > > They will be the one taking the patch. > > And when dealing with PM on AT91, please copy > Wenyou Yang > > > On 16/01/2015 at 20:41:14 +0100, Sylvain Rochet wrote : > > This patch add suspend/resume support for Atmel EHCI, mostly > > about disabling and unpreparing clocks so USB PLL is stopped > > before entering sleep state. > > > > Signed-off-by: Sylvain Rochet > > Acked-by: Alexandre Belloni > > > + > > + if (at91_suspend_entering_slow_clock()) > > + atmel_stop_clock(); > > + > > We should definitely find a way to get rid of > at91_suspend_entering_slow_clock() at some point in time. > > Can't we just disable clocks without testing for target_state == PM_SUSPEND_MEM (which is exactly what at91_suspend_entering_slow_clock does [1]) when entering suspend ? I mean, IMHO other kind of suspend should still benefit from the power save induced by this PLL deactivation. Is there such a big penalty when resuming the device if the PLL and peripheral clocks are disabled ? [1]http://lxr.free-electrons.com/source/arch/arm/mach-at91/pm.c#L116 -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com