[PATCH] USB: host: ehci_atmel: Add suspend/resume support
boris.brezillon at free-electrons.com
Sat Jan 17 01:36:09 PST 2015
On Sat, 17 Jan 2015 02:34:42 +0100
Alexandre Belloni <alexandre.belloni at free-electrons.com> wrote:
> You should probably put the susbsytem maintainers in copy too. As
> reported by get_maintainer.pl:
> Alan Stern <stern at rowland.harvard.edu> (maintainer:USB EHCI DRIVER)
> Greg Kroah-Hartman <gregkh at linuxfoundation.org> (supporter:USB SUBSYSTEM)
> They will be the one taking the patch.
> And when dealing with PM on AT91, please copy
> Wenyou Yang <wenyou.yang at atmel.com>
> 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 <sylvain.rochet at finsecur.com>
> Acked-by: Alexandre Belloni <alexandre.belloni at free-electrons.com>
> > +
> > + 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 ) 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 ?
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
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