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SubjectRe: [PATCH 1/2] soc: qcom: rpmhpd: Use corner in power_off
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On 07/07/2021 18:48, Bjorn Andersson wrote:
> On Wed 07 Jul 01:31 CDT 2021, Rajendra Nayak wrote:
>
>>
>>
>> On 7/7/2021 10:19 AM, Bjorn Andersson wrote:
>>> On Mon 05 Jul 00:40 CDT 2021, Rajendra Nayak wrote:
>>>> On 7/5/2021 10:36 AM, Bjorn Andersson wrote:
>>>>> On Sun, Jul 4, 2021 at 11:27 PM Rajendra Nayak <rnayak@codeaurora.org> wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>> On 7/3/2021 6:24 AM, Bjorn Andersson wrote:
>>>>>>> rpmhpd_aggregate_corner() takes a corner as parameter, but in
>>>>>>> rpmhpd_power_off() the code requests the level of the first corner
>>>>>>> instead.
>>>>>>>
>>>>>>> In all (known) current cases the first corner has level 0, so this
>>>>>>> change should be a nop, but in case that there's a power domain with a
>>>>>>> non-zero lowest level this makes sure that rpmhpd_power_off() actually
>>>>>>> requests the lowest level - which is the closest to "power off" we can
>>>>>>> get.
>>>>>>>
>>>>>>> While touching the code, also skip the unnecessary zero-initialization
>>>>>>> of "ret".
>>>>>>>
>>>>>>> Fixes: 279b7e8a62cc ("soc: qcom: rpmhpd: Add RPMh power domain driver")
>>>>>>> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
>>>>>>> ---
>>>>>>> drivers/soc/qcom/rpmhpd.c | 5 ++---
>>>>>>> 1 file changed, 2 insertions(+), 3 deletions(-)
>>>>>>>
>>>>>>> diff --git a/drivers/soc/qcom/rpmhpd.c b/drivers/soc/qcom/rpmhpd.c
>>>>>>> index 2daa17ba54a3..fa209b479ab3 100644
>>>>>>> --- a/drivers/soc/qcom/rpmhpd.c
>>>>>>> +++ b/drivers/soc/qcom/rpmhpd.c
>>>>>>> @@ -403,12 +403,11 @@ static int rpmhpd_power_on(struct generic_pm_domain *domain)
>>>>>>> static int rpmhpd_power_off(struct generic_pm_domain *domain)
>>>>>>> {
>>>>>>> struct rpmhpd *pd = domain_to_rpmhpd(domain);
>>>>>>> - int ret = 0;
>>>>>>> + int ret;
>>>>>>>
>>>>>>> mutex_lock(&rpmhpd_lock);
>>>>>>>
>>>>>>> - ret = rpmhpd_aggregate_corner(pd, pd->level[0]);
>>>>>>> -
>>>>>>> + ret = rpmhpd_aggregate_corner(pd, 0);
>>>>>>
>>>>>> This won't work for cases where pd->level[0] != 0, rpmh would just ignore this and keep the
>>>>>> resource at whatever corner it was previously at.
>>>>>> (unless command DB tells you a 0 is 'valid' for a resource, sending a 0 is a nop)
>>>>>> The right thing to do is to send in whatever command DB tells you is the lowest level that's valid,
>>>>>> which is pd->level[0].
>>>>>>
>>>>>
>>>>> I'm afraid this doesn't make sense to me.
>>>>>
>>>>> In rpmh_power_on() if cmd-db tells us that we have [0, 64, ...] and we
>>>>> request 64 we rpmhpd_aggregate_corner(pd, 1); but in power off, if
>>>>> cmd-db would provide [64, ...] we would end up sending
>>>>> rpmhpd_aggregate_corner(pd, 64);
>>>>> So in power_on we request the corner (i.e. index in the array provided
>>>>> in cmd-db) and in power-off the same function takes the level?
>>>>
>>>> ah that's right, I did not read the commit log properly and got confused.
>>>
>>> Thanks for confirming my understanding.
>>>
>>>> Looks like this bug existed from the day this driver for merged :/, thanks
>>>> for catching it.
>>>> Does it make sense to also mark this fix for stable?
>>>>
>>>
>>> I can certainly add a Cc: stable@ as I'm applying this.
>>
>> sure, sounds good
>>> May I have your R-b?
>>
>> Reviewed-by: Rajendra Nayak <rnayak@codeaurora.org>
>>
>
> Thank you.
>
>>>
>>> PS. Do you have any input on patch 2/2? That actually solves a practical
>>> problem we're seeing. Would it perhaps aid in your need for the new
>>> "assigned-opp-level" property?
>>
>> We would perhaps still need the 'assigned-opp-level' or equivalent since
>> the default requirement of devices is not always the least level supported,
>> in some cases it might be slightly higher corner which would then need to
>> be set explicitly.
>>
>
> Right, for situations where we use assign-clock-rates to drive up the
> clock rate this mechanism might be needed in order to keep things
> stable.
>
> But I presume as soon as you have some sort of dynamic nature to that
> you'll be back to an opp-table and the means we already have.
>
>> I was hoping on getting some more testing done with that patch especially for
>> any regression on the sc7180 and sc7280 devices, which I haven't got to yet.
>> Are you getting these patches ready for merge for the -rc cycle or for the
>> next merge window?
>>
>
> That would be much appreciated, I've not done extensive testing myself,
> mostly just booted a few different boards.
>
> But I would like to see us correct the MDSS_GDSC->MMCX setup in time for
> v5.15, in particular since we have a few new users of the mmcx
> power-domain-regulator arriving in this cycle.

I will rebase my patches on top of this patch series and submit soon.


--
With best wishes
Dmitry

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