ARM: dts: rockchip: Mark that the rk3288 timer might stop in suspend
diff mbox series

Message ID 20190521234933.153953-1-dianders@chromium.org
State New
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Series
  • ARM: dts: rockchip: Mark that the rk3288 timer might stop in suspend
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Commit Message

Doug Anderson May 21, 2019, 11:49 p.m. UTC
This is similar to commit e6186820a745 ("arm64: dts: rockchip: Arch
counter doesn't tick in system suspend").  Specifically on the rk3288
it can be seen that the timer stops ticking in suspend if we end up
running through the "osc_disable" path in rk3288_slp_mode_set().  In
that path the 24 MHz clock will turn off and the timer stops.

To test this, I ran this on a Chrome OS filesystem:
  before=$(date); \
  suspend_stress_test -c1 --suspend_min=30 --suspend_max=31; \
  echo ${before}; date

...and I found that unless I plug in a device that requests USB wakeup
to be active that the two calls to "date" would show that fewer than
30 seconds passed.

NOTE: deep suspend (where the 24 MHz clock gets disabled) isn't
supported yet on upstream Linux so this was tested on a downstream
kernel.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
---

 arch/arm/boot/dts/rk3288.dtsi | 1 +
 1 file changed, 1 insertion(+)

Comments

Heiko Stuebner May 22, 2019, 8:04 a.m. UTC | #1
Am Mittwoch, 22. Mai 2019, 01:49:33 CEST schrieb Douglas Anderson:
> This is similar to commit e6186820a745 ("arm64: dts: rockchip: Arch
> counter doesn't tick in system suspend").  Specifically on the rk3288
> it can be seen that the timer stops ticking in suspend if we end up
> running through the "osc_disable" path in rk3288_slp_mode_set().  In
> that path the 24 MHz clock will turn off and the timer stops.
> 
> To test this, I ran this on a Chrome OS filesystem:
>   before=$(date); \
>   suspend_stress_test -c1 --suspend_min=30 --suspend_max=31; \
>   echo ${before}; date
> 
> ...and I found that unless I plug in a device that requests USB wakeup
> to be active that the two calls to "date" would show that fewer than
> 30 seconds passed.
> 
> NOTE: deep suspend (where the 24 MHz clock gets disabled) isn't
> supported yet on upstream Linux so this was tested on a downstream
> kernel.
> 
> Signed-off-by: Douglas Anderson <dianders@chromium.org>

applied for 5.3

Patch
diff mbox series

diff --git a/arch/arm/boot/dts/rk3288.dtsi b/arch/arm/boot/dts/rk3288.dtsi
index 171231a0cd9b..1e5260b556b7 100644
--- a/arch/arm/boot/dts/rk3288.dtsi
+++ b/arch/arm/boot/dts/rk3288.dtsi
@@ -231,6 +231,7 @@ 
 			     <GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_HIGH)>,
 			     <GIC_PPI 10 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_HIGH)>;
 		clock-frequency = <24000000>;
+		arm,no-tick-in-suspend;
 	};
 
 	timer: timer@ff810000 {