linux-kernel - Re: [PATCH V2] cpufreq: tegra186: Fix initial frequency

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Message-ID: <c6ab92fe-e5ea-4568-6457-7a28c8496114@nvidia.com>
Date:   Mon, 26 Oct 2020 12:57:07 +0000
From:   Jon Hunter <jonathanh@...dia.com>
To:     Viresh Kumar <viresh.kumar@...aro.org>
CC:     "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Thierry Reding <thierry.reding@...il.com>,
        <linux-pm@...r.kernel.org>, <linux-tegra@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V2] cpufreq: tegra186: Fix initial frequency


On 19/10/2020 10:33, Jon Hunter wrote:
> 
> On 16/10/2020 05:07, Viresh Kumar wrote:
>> On 15-10-20, 15:03, Jon Hunter wrote:
>>> If not too late, would you mind dropping this patch for v5.10?
>>
>> It is already part of Linus's master now.
> 
> OK, thanks. I will send a revert for this once rc1 is out.


Thinking about this some more, what are your thoughts on making the
following change? 

Basically, if the driver sets the CPUFREQ_NEED_INITIAL_FREQ_CHECK,
then I wonder if we should not fail if the frequency return by
>get() is not known. This would fix the problem I see on Tegra186
where the initial boot frequency may not be in the frequency table.

Cheers
Jon

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index f4b60663efe6..b7d3b61577b0 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1426,13 +1426,8 @@ static int cpufreq_online(unsigned int cpu)
                                CPUFREQ_CREATE_POLICY, policy);
        }
 
-       if (cpufreq_driver->get && has_target()) {
+       if (cpufreq_driver->get && has_target())
                policy->cur = cpufreq_driver->get(policy->cpu);
-               if (!policy->cur) {
-                       pr_err("%s: ->get() failed\n", __func__);
-                       goto out_destroy_policy;
-               }
-       }
 
        /*
         * Sometimes boot loaders set CPU frequency to a value outside of
@@ -1471,6 +1466,11 @@ static int cpufreq_online(unsigned int cpu)
                        pr_info("%s: CPU%d: Running at unlisted initial frequency: %u KHz, changing to: %u KHz\n",
                                __func__, policy->cpu, old_freq, policy->cur);
                }
+       } else {
+               if (!policy->cur) {
+                       pr_err("%s: ->get() failed\n", __func__);
+                       goto out_destroy_policy;
+               }
        }
 
        if (new_policy) {

-- 
nvpublic