cpuidle big_little driver on Odroid-xu4

cpuidle big_little driver on Odroid-xu4

[Jaafar Ali]

Dear Sylwester,
Kernel 5.3rc1
Hardware Odroid-XU4
cpuidle-big_little driver for exynos 5422 of odroid-xu3/4 is not working.
when I enable it in the defconfig , CONFIG_ARM_BIG_LITTLE_CPUIDLE=y,
the device will not boot and the heartbeat blue LED stops.
when the powerdown state[1] is removed form cpuidle-big_little driver
or the function bl_enter_powerdown is disabled by early return, the
kernel boots successfully and I can see cpuidle driver inside
/sys/devices/system/cpu/cpuidle/current_driver
both cpuidle-big_little power down state (exynos5420) and suspend
stuff are using mcpm_cpu_suspend() which in turn calls
mcpm_cpu_power_down() eventually.
while suspend stuff is working correctly and the cpu can
suspend/resume without problems, the cpuidle-bl is not working
the few difference between suspend.c and cpuidle-big_little that I
found are suspend.c do some more preparations such as storing resume
entry point "mcpm_entry_point" into S5P_INFORM0, reset
EXYNOS5420_CPU_STATE and save and restore some other registers.
Can we repeat the scenario of suspend in cpuidle-big_little

Best Regards
-- 
Jaafar Khalaf

Re: cpuidle big_little driver on Odroid-xu4

[Krzysztof Kozlowski]

On Sun, 1 Sep 2019 at 15:19, Jaafar Ali <jaafarkhalaf@gmail.com> wrote:
>
> Dear Sylwester,
> Kernel 5.3rc1
> Hardware Odroid-XU4
> cpuidle-big_little driver for exynos 5422 of odroid-xu3/4 is not working.
> when I enable it in the defconfig , CONFIG_ARM_BIG_LITTLE_CPUIDLE=y,
> the device will not boot and the heartbeat blue LED stops.
> when the powerdown state[1] is removed form cpuidle-big_little driver
> or the function bl_enter_powerdown is disabled by early return, the
> kernel boots successfully and I can see cpuidle driver inside
> /sys/devices/system/cpu/cpuidle/current_driver
> both cpuidle-big_little power down state (exynos5420) and suspend
> stuff are using mcpm_cpu_suspend() which in turn calls
> mcpm_cpu_power_down() eventually.
> while suspend stuff is working correctly and the cpu can
> suspend/resume without problems, the cpuidle-bl is not working
> the few difference between suspend.c and cpuidle-big_little that I
> found are suspend.c do some more preparations such as storing resume
> entry point "mcpm_entry_point" into S5P_INFORM0, reset
> EXYNOS5420_CPU_STATE and save and restore some other registers.
> Can we repeat the scenario of suspend in cpuidle-big_little

Hi Jaafar,

Thank you for the report. I am not sure whether big-little cpuidle was
working properly before... (before v5.3-rc1) I added your report to
https://exynos.wiki.kernel.org/todo_tasks

Best regards,
Krzysztof