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platform/x86/intel-uncore-freq: Fix current_freq_khz after CPU hotplug

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When the last CPU of a legacy uncore die goes offline,
uncore_freq_remove_die_entry() clears control_cpu. During CPU hotplug
re-add, uncore_freq_add_entry() still populates sysfs attributes before
assigning the new control CPU. As a result, the current frequency read
returns -ENXIO and current_freq_khz is omitted from the recreated sysfs
group.

Assign control_cpu before the initial read paths and before
create_attr_group() so sysfs recreation uses the new online CPU. If
sysfs creation fails, restore control_cpu to -1 to keep the error path
state consistent.

Fixes: 4d73c6772a ("platform/x86: intel-uncore-freq: Conditionally create attribute for read frequency")
Cc: stable@vger.kernel.org
Signed-off-by: Guixiong Wei <weiguixiong@bytedance.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://patch.msgid.link/20260602020752.3126-1-weiguixiong@bytedance.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
This commit is contained in:
Guixiong Wei 2026-06-02 10:07:52 +08:00 committed by Ilpo Järvinen
parent c085d82613
commit 6b63520ed1
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GPG Key ID: 59AC4F6153E5CE31
1 changed files with 6 additions and 1 deletions
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drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c
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@ -285,15 +285,20 @@ int uncore_freq_add_entry(struct uncore_data *data, int cpu)
data->package_id, data->die_id);
}
/*
* Set the control CPU before any read path so entry recreation after CPU
* hotplug can populate read-only attributes from the new online CPU.
*/
data->control_cpu = cpu;
uncore_read(data, &data->initial_min_freq_khz, UNCORE_INDEX_MIN_FREQ);
uncore_read(data, &data->initial_max_freq_khz, UNCORE_INDEX_MAX_FREQ);
ret = create_attr_group(data, data->name);
if (ret) {
data->control_cpu = -1;
if (data->domain_id != UNCORE_DOMAIN_ID_INVALID)
ida_free(&intel_uncore_ida, data->seqnum_id);
} else {
data->control_cpu = cpu;
data->valid = true;
}