* Grygorii Strashko <[email protected]> [161129 08:43]: > > > On 11/24/2016 12:19 AM, Keerthy wrote: > > From: Grygorii Strashko <[email protected]> > > > > Now ARM Global timer (rating 300) will not be selected as clocksource, > > because it's initialized after OMAP GP Timer (rating 300) and > > Timekeeping core will not allow to replace clocksource with new one if > > both of them have the same rating. > > > > Reduce rating of OMAP GP Timer (300->290) when it's used as > > clocksource device - this will allow to select ARM Global timer (300) > > as clocksource when enabled. > > > > Signed-off-by: Grygorii Strashko <[email protected]> > > Signed-off-by: Dave Gerlach <[email protected]> > > Signed-off-by: Keerthy <[email protected]> > > Unfortunately, this patch has dependency [1] and can't be used alone as > it will cause ARM Global timer to be selected as clocksource > always on am437x and this will kill cpuidle, because ARM Global timer > is not in always_on domain. > > The intention of enabling ARM Global timer is only for non-pm aware use > cases for RT-kernel latency improvement - where deep cpuidle states are not > enabled.
Yeah we need to fix up things to be able to change the clocksource in addition to clockevent. However, currently only cpuidle_coupled knows when the whole system is idle, so quite a bit of work is needed to do that in a sane way. What about the first patch in this series? Regards, Tony > [1] https://patchwork.kernel.org/patch/8940051/ > > > --- > > arch/arm/mach-omap2/timer.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c > > index b2f2448..a0dbb0b 100644 > > --- a/arch/arm/mach-omap2/timer.c > > +++ b/arch/arm/mach-omap2/timer.c > > @@ -376,7 +376,7 @@ static cycle_t clocksource_read_cycles(struct > > clocksource *cs) > > } > > > > static struct clocksource clocksource_gpt = { > > - .rating = 300, > > + .rating = 290, > > .read = clocksource_read_cycles, > > .mask = CLOCKSOURCE_MASK(32), > > .flags = CLOCK_SOURCE_IS_CONTINUOUS, > > > > -- > regards, > -grygorii
