| Message ID | 1485260203-14216-5-git-send-email-al.kochet@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Jan 24, 2017 at 03:16:39PM +0300, Alexander Kochetkov wrote: > clocksource and shed_clock provided by arm-global-timer is quite > unstable, because their rate depends on cpu frequency. > So disable arm-global-timer and use clocksource and sched_clock > from rockchip_timer. > It is impossible get stable clocksource having rockchip_timer and > arm-global-timer enabled at the same time. Because arm-global-timer > looks like a better candidate for the kernel: it has higher > frequency and rating. > > Disabling arm-global-timer doesn't leave kernel without > clockevents as there is another clockevent provider (smp-twd). Hi Alexander, sorry, I will rewrite the description because of the grammatical errors. I don't want to give you the feeling I'm lecturing you, my English is not perfect but it will be simpler to give the full descr with the typos fixed. " The clocksource and the sched_clock provided by the arm_global_timer are quite unstable because their rates depend on the cpu frequency. On the other side, the arm_global_timer has a higher rating than the rockchip_timer, it will be selected by default by the time framework while we want to use the stable rockchip clocksource. Let's disable the arm_global_timer in order to have the rockchip clocksource selected by default. " This patch should go at the end of the patchset when the clocksource is implemented in the rockchip_timer. > Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com> > Reviwed-by: Heiko Stübner <heiko@sntech.de> > --- > arch/arm/boot/dts/rk3188.dtsi | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/arm/boot/dts/rk3188.dtsi b/arch/arm/boot/dts/rk3188.dtsi > index bcf8e03..f677130 100644 > --- a/arch/arm/boot/dts/rk3188.dtsi > +++ b/arch/arm/boot/dts/rk3188.dtsi > @@ -546,6 +546,7 @@ > > &global_timer { > interrupts = <GIC_PPI 11 0xf04>; > + status = "disabled"; > }; > > &local_timer { > -- > 1.7.9.5 >
diff --git a/arch/arm/boot/dts/rk3188.dtsi b/arch/arm/boot/dts/rk3188.dtsi index bcf8e03..f677130 100644 --- a/arch/arm/boot/dts/rk3188.dtsi +++ b/arch/arm/boot/dts/rk3188.dtsi @@ -546,6 +546,7 @@ &global_timer { interrupts = <GIC_PPI 11 0xf04>; + status = "disabled"; }; &local_timer {
clocksource and shed_clock provided by arm-global-timer is quite unstable, because their rate depends on cpu frequency. So disable arm-global-timer and use clocksource and sched_clock from rockchip_timer. It is impossible get stable clocksource having rockchip_timer and arm-global-timer enabled at the same time. Because arm-global-timer looks like a better candidate for the kernel: it has higher frequency and rating. Disabling arm-global-timer doesn't leave kernel without clockevents as there is another clockevent provider (smp-twd). Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com> Reviwed-by: Heiko Stübner <heiko@sntech.de> --- arch/arm/boot/dts/rk3188.dtsi | 1 + 1 file changed, 1 insertion(+)