[PATCH 10/10] ARM: imx6q: implement WAIT mode with coupled cpuidle

[Lorenzo Pieralisi]

On Wed, Oct 24, 2012 at 02:57:31PM +0100, Shawn Guo wrote:
> On Tue, Oct 23, 2012 at 06:35:43PM +0100, Lorenzo Pieralisi wrote:
> > On Tue, Oct 23, 2012 at 04:22:59PM +0100, Shawn Guo wrote:
> > 
> > [...]
> > 
> > > +/*
> > > + * For each cpu, setup the broadcast timer because local timer
> > > + * stops for the states other than WFI.
> > > + */
> > > +static void imx6q_setup_broadcast_timer(void *arg)
> > > +{
> > > +       int cpu = smp_processor_id();
> > > +
> > > +       clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ON, &cpu);
> > > +}
> > 
> > Can anyone explain to me please why this is needed ?
> > 
> It basically does nothing if either NO_HZ or HIGH_RES_TIMERS is
> enabled, in which case tick_broadcast_setup_oneshot is already called
> on init_timers path to set up bc->event_handler.  This is the general
> case since nowadays we have both options enabled by default for most
> systems.
> 
> However if neither option is enabled, CLOCK_EVT_NOTIFY_BROADCAST_ON
> notifying will help route to call tick_broadcast_setup_oneshot to have
> bc->event_handler set up.
> 
> So in short, it's needed to have broadcast timer work as expected when
> neither NO_HZ or HIGH_RES_TIMERS is enabled.

Ok, point taken, it was just to check I was not missing anything on the
expected usage on systems where those options are enabled.

Thanks a lot,
Lorenzo