Re: [Patch] cpufreq: tegra194: remove opp table in exit hook

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Add exit hook and remove OPP table when all the CPU's in a policy
are offlined. It will fix the below error messages when onlining
first CPU from a policy whose all CPU's were previously offlined.

   debugfs: File 'cpu5' in directory 'opp' already present!
   debugfs: File 'cpu6' in directory 'opp' already present!
   debugfs: File 'cpu7' in directory 'opp' already present!

Fixes: f41e1442ac5b ("cpufreq: tegra194: add OPP support and set bandwidth")
Signed-off-by: Sumit Gupta <sumitg@xxxxxxxxxx>
   drivers/cpufreq/tegra194-cpufreq.c | 13 +++++++++++++
   1 file changed, 13 insertions(+)

diff --git a/drivers/cpufreq/tegra194-cpufreq.c b/drivers/cpufreq/tegra194-cpufreq.c
index c90b30469165..66a9c23544db 100644
--- a/drivers/cpufreq/tegra194-cpufreq.c
+++ b/drivers/cpufreq/tegra194-cpufreq.c
@@ -454,6 +454,8 @@ static int tegra_cpufreq_init_cpufreq_table(struct cpufreq_policy *policy,
                if (ret < 0)
                        return ret;

+             dev_pm_opp_put(opp);
                freq_table[j].driver_data = pos->driver_data;
                freq_table[j].frequency = pos->frequency;
@@ -508,6 +510,16 @@ static int tegra194_cpufreq_init(struct cpufreq_policy *policy)
        return 0;

+static int tegra194_cpufreq_exit(struct cpufreq_policy *policy)
+     struct device *cpu_dev = get_cpu_device(policy->cpu);
+     dev_pm_opp_remove_all_dynamic(cpu_dev);
+     dev_pm_opp_of_cpumask_remove_table(policy->related_cpus);
+     return 0;
   static int tegra194_cpufreq_set_target(struct cpufreq_policy *policy,
                                       unsigned int index)
@@ -535,6 +547,7 @@ static struct cpufreq_driver tegra194_cpufreq_driver = {
        .target_index = tegra194_cpufreq_set_target,
        .get = tegra194_get_speed,
        .init = tegra194_cpufreq_init,
+     .exit = tegra194_cpufreq_exit,
        .attr = cpufreq_generic_attr,

If it is only about hotplugging of the CPUs, then you can also do this I guess.

commit 263abfe74b5f ("cpufreq: dt: Implement online/offline() callbacks")

You should do this as well, this makes hotplugging paths much faster. i.e. on
top of this patch.

Sent a separate patch to add online/offline callbacks.

Also, sent v2 of this patch with updated commit description.

Thank you,
Sumit Gupta

But since your driver is capable of being built as a module, I suggest you try
to build it as one and insert remove it multiple times. It must cause you some
trouble as you don't implement an .exit() before this patch.

Eventually, I think you need to do both, what this patch and 263abfe74b5f do.
Just that the reasons need to be correct for both the changes.


Hi Viresh,
I got the same message on inserting and removing the module multiple times
as you suggested. After applying this change, the message is not coming. So,
the current change is resolving both scenarios as __cpufreq_offline() calls
either exit() or offline().
I can update the commit message to mention both scenarios and keep change as
it is?




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