Re: CPUIdle for Exynos5422 Odroid-XU3/XU4 boards.

[Przemyslaw Marczak <p.marczak@samsung.com>]

Hi all,

On 08/21/2015 09:21 AM, Javier Martinez Canillas wrote:
> [Adding Przemyslaw Marczak who was working on porting Odroid BL1/BL2/SPL]

This work is currently on hold, but the mainline spl support will not 
solve early-boot issues caused by cpu running in a non-secure state.
But I think, that still some hacking is possible, and will continue a 
research on it later, when I finish some more important tasks.

Best regards,
-- 
Przemyslaw Marczak
Samsung R&D Institute Poland
Samsung Electronics
p.marczak@samsung.com

>
> Hello,
>
> On 08/21/2015 05:59 AM, Krzysztof Kozlowski wrote:
>> On 21.08.2015 12:41, Anand Moon wrote:
>>> Hi Krzysztof,
>>>
>>> On 21 August 2015 at 06:25, Krzysztof Kozlowski <k.kozlowski@samsung.com> wrote:
>>>> On 21.08.2015 03:15, Anand Moon wrote:
>>>>> Hi Daniel,
>>>>>
>>>>> On 20 August 2015 at 21:40, Daniel Lezcano <daniel.lezcano@free.fr> wrote:
>>>>>> On 08/20/2015 12:54 PM, Anand Moon wrote:
>>>>>>>
>>>>>>> Hello Krzysztof/Kukjim,
>>>>>>>
>>>>>>> CPUIdle seen to be not working for Exynos5422 Odroid boards.
>>>>>>>
>>>>>>> Is their any way this feature will be implemented in the future.
>>>>>>
>>>>>>
>>>>>> Yeah a good willing to fix the bl1. More than one year asking for that !
>>>>>> nooo way !!
>>>>>>
>>>>>> Your answer is at the end of
>>>>>> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-June/350632.html
>>>>>>
>>>>>>
>>>>>
>>>>> Thanks for the explanation.
>>>>>
>>>>> I was just referring following the source code.
>>>>>
>>>>> https://github.com/hardkernel/linux/blob/odroidxu3-3.10.y/arch/arm/mach-exynos/cpuidle-exynos5422.c
>>>>>
>>>>> It seem that cpufreq and cpuidle go hand in hand.
>>>>
>>>> Bartlomiej was working on cpufreq for Exynos542x:
>>>> http://lkml.iu.edu/hypermail/linux/kernel/1504.2/03139.html
>>>>
>>>> It would be nice to have also cpuidle and suspend features working on
>>>> Exynos542x family but this depends on firmware. Some time ago I
>>>> struggled with suspend on Arndale Octa (Exynos5420) and I failed. I
>>>> think the firmware is the issue here.
>
> There were a lot of Suspend-to-RAM bug fixes lately mostly related to
> critical clocks being gated. It would be nice to give a try on recent
> kernels and see if is still not working.
>
>>>>
>>>> Actually I am not sure what is your question Anand. You are asking if
>>>> someone plans to do this?
>>>
>>> Yes I am asking are their plans to implement cpufreq and cpuidle simultaneously.
>>
>> There are no obstacles for implementing them simultaneously so the
>> question is rather who plans to do the cpuidle driver for Exynos542x? I
>
> If the firmware is in a good shape (unfortunately as mentioned by Daniel,
> the one in the Odroids are not) then the generic ARM big.LITTLE CPUidle
> driver (CONFIG_ARM_BIG_LITTLE_CPUIDLE) should work.
>
> It is at least working for me on the Exynos5800 based Peach Pi Chromebook:
>
> $ cat /sys/devices/system/cpu/cpuidle/current_driver
> big_idle
>
> $ cat /sys/devices/system/cpu/cpu0/cpuidle/state*/name
> WFI
> C1
>
> $ cat /sys/devices/system/cpu/cpu0/cpuidle/state*/usage
> 7745
> 10578
>
>> don't... at least in nearby future. If I had some spare time then
>> probably I would try to make suspend working.
>>
>
> Suspend-to-RAM is at least working on the Exynos5420 and Exynos5800
> Chromebooks.
>
> As you mentioned it may depend on the firmware so that does not hold
> true for all the Exynos5420/5422/5800 boards but it would be good to
> know what is the causing S2R to fail.
>
>> Best regards,
>> Krzysztof
>>
>
> Best regards,
>