[PATCH] drm/i915/pmu: Drop custom hotplug code

[Lucas De Marchi]

On Mon, Jan 20, 2025 at 08:42:41PM -0500, Liang, Kan wrote:
>>>> -static int i915_pmu_cpu_offline(unsigned int cpu, struct hlist_node
>>>> *node)
>>>> -{
>>>> -    struct i915_pmu *pmu = hlist_entry_safe(node, typeof(*pmu),
>>>> cpuhp.node);
>>>> -    unsigned int target = i915_pmu_target_cpu;
>>>> -
>>>> -    /*
>>>> -     * Unregistering an instance generates a CPU offline event which
>>>> we must
>>>> -     * ignore to avoid incorrectly modifying the shared
>>>> i915_pmu_cpumask.
>>>> -     */
>>>> -    if (!pmu->registered)
>>>> -        return 0;
>>>> -
>>>> -    if (cpumask_test_and_clear_cpu(cpu, &i915_pmu_cpumask)) {
>>>> -        target = cpumask_any_but(topology_sibling_cpumask(cpu), cpu);
>>>> -
>>>
>>> I'm not familar with the i915 PMU, but it seems suggest a core scope
>>> PMU, not a system-wide scope.
>>
>> counter is in a complete separate device - it doesn't depend on core or
>> die or pkg - not sure why it cared about topology_sibling_cpumask here.
>
>OK. But it's still a behavior change. Please make it clear in the
>description that the patch also changes/fixes the scope from core scope
>to system-wide.

sure... do you have a suggestion how to test the hotplug? For testing
purposes, can I force the perf cpu assigned to be something other than
the cpu0?

thanks
Lucas De Marchi