Messages in this thread | | | Subject | Re: [PATCH 2/2] ARM: omap: timers: reduce rating of gp_timer clocksource | From | Grygorii Strashko <> | Date | Fri, 2 Dec 2016 12:02:23 -0600 |
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On 12/02/2016 10:47 AM, Tony Lindgren wrote: > * Grygorii Strashko <grygorii.strashko@ti.com> [161129 08:43]: >> >> >> On 11/24/2016 12:19 AM, Keerthy wrote: >>> From: Grygorii Strashko <grygorii.strashko@ti.com> >>> >>> 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 <grygorii.strashko@ti.com> >>> Signed-off-by: Dave Gerlach <d-gerlach@ti.com> >>> Signed-off-by: Keerthy <j-keerthy@ti.com> >> >> 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.
Also sched_clock and timer_delay ;)
> > What about the first patch in this series? >
Fist one is ok. It was originally posted long time ago.
-- regards, -grygorii
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