linux-kernel - Re: [PATCH 1/2] soc: qcom: rpmhpd: Use corner in power

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Message-ID: <cacd1a1f-01c8-b913-23e5-538a772cd118@codeaurora.org>
Date:   Mon, 5 Jul 2021 09:56:47 +0530
From:   Rajendra Nayak <rnayak@...eaurora.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc:     linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] soc: qcom: rpmhpd: Use corner in power_off



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@...aro.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].


>   	if (!ret)
>   		pd->enabled = false;
>   
> 

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