Re: [PATCH] cpufreq: vexpress-spc: Fix wrong alternation of policy->related_cpus during CPU hp

From: Viresh Kumar
Date: Wed Nov 27 2019 - 21:31:23 EST


On 27-11-19, 15:40, Sudeep Holla wrote:
> diff --git i/arch/arm/mach-vexpress/spc.c w/arch/arm/mach-vexpress/spc.c
> index 354e0e7025ae..e0e2e789a0b7 100644
> --- i/arch/arm/mach-vexpress/spc.c
> +++ w/arch/arm/mach-vexpress/spc.c
> @@ -551,8 +551,9 @@ static struct clk *ve_spc_clk_register(struct device *cpu_dev)
>
> static int __init ve_spc_clk_init(void)
> {
> - int cpu;
> + int cpu, cluster;
> struct clk *clk;
> + bool init_opp_table[MAX_CLUSTERS] = { false };
>
> if (!info)
> return 0; /* Continue only if SPC is initialised */
> @@ -578,8 +579,17 @@ static int __init ve_spc_clk_init(void)
> continue;
> }
>
> + cluster = topology_physical_package_id(cpu_dev->id);
> + if (init_opp_table[cluster])
> + continue;
> +
> if (ve_init_opp_table(cpu_dev))
> pr_warn("failed to initialise cpu%d opp table\n", cpu);
> + else if (dev_pm_opp_set_sharing_cpus(cpu_dev,
> + topology_core_cpumask(cpu_dev->id)))
> + pr_warn("failed to mark OPPs shared for cpu%d\n", cpu);
> +
> + init_opp_table[cluster] = true;
> }
>
> platform_device_register_simple("vexpress-spc-cpufreq", -1, NULL, 0);
> diff --git i/drivers/cpufreq/vexpress-spc-cpufreq.c w/drivers/cpufreq/vexpress-spc-cpufreq.c
> index 506e3f2bf53a..83c85d3d67e3 100644
> --- i/drivers/cpufreq/vexpress-spc-cpufreq.c
> +++ w/drivers/cpufreq/vexpress-spc-cpufreq.c
> @@ -434,7 +434,7 @@ static int ve_spc_cpufreq_init(struct cpufreq_policy *policy)
> if (cur_cluster < MAX_CLUSTERS) {
> int cpu;
>
> - cpumask_copy(policy->cpus, topology_core_cpumask(policy->cpu));
> + dev_pm_opp_get_sharing_cpus(cpu_dev, policy->cpus);
>
> for_each_cpu(cpu, policy->cpus)
> per_cpu(physical_cluster, cpu) = cur_cluster;

This is a better *work-around* I would say, as we can't break it the
way I explained earlier :)

--
viresh