On Mon 2019-08-05 15:02:17, Greg Kroah-Hartman wrote:
[ Upstream commit 8ef1ba39a9fa53d2205e633bc9b21840a275908e ]
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.
I guess this does no harm, but deep sleep is unlikely to be suppored in the stable kernels, so ... is it good idea there?
Thanks, Pavel
--- a/arch/arm/boot/dts/rk3288.dtsi +++ b/arch/arm/boot/dts/rk3288.dtsi @@ -227,6 +227,7 @@ <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 {