linux-kernel - Re: [PATCH] PM / OPP: Update performance state when freq == old

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Message-ID: <12337613.44RoPr5aty@aspire.rjw.lan>
Date:   Wed, 13 Mar 2019 10:56:44 +0100
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...nel.org>, linux-pm@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        jorge.ramirez-ortiz@...aro.org, "v5 . 0" <stable@...r.kernel.org>,
        Niklas Cassel <niklas.cassel@...aro.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] PM / OPP: Update performance state when freq == old_freq

On Tuesday, March 12, 2019 5:57:18 AM CET Viresh Kumar wrote:
> At boot up, CPUfreq core performs a sanity check to see if the system is
> running at a frequency defined in the frequency table of the CPU. If so,
> we try to find a valid frequency (lowest frequency greater than the
> currently programmed frequency) from the table and set it. When the call
> reaches dev_pm_opp_set_rate(), it calls _find_freq_ceil(opp_table,
> &old_freq) to find the previously configured OPP and this call also
> updates the old_freq. This eventually sets the old_freq == freq (new
> target requested by cpufreq core) and we skip updating the performance
> state in this case.
> 
> Fix this by also updating the performance state when the old_freq ==
> freq.
> 
> Fixes: ca1b5d77b1c6 ("OPP: Configure all required OPPs")
> Cc: v5.0 <stable@...r.kernel.org> # v5.0
> Reported-by: Niklas Cassel <niklas.cassel@...aro.org>
> Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
> ---
>  drivers/opp/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/opp/core.c b/drivers/opp/core.c
> index d7f97167cac3..0420f7e8ad5b 100644
> --- a/drivers/opp/core.c
> +++ b/drivers/opp/core.c
> @@ -760,7 +760,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
>  		old_freq, freq);
>  
>  	/* Scaling up? Configure required OPPs before frequency */
> -	if (freq > old_freq) {
> +	if (freq >= old_freq) {
>  		ret = _set_required_opps(dev, opp_table, opp);
>  		if (ret)
>  			goto put_opp;
> 

Applied, thanks!