Commit 05ff1ba4 authored Nov 20, 2019 by Rafael J. Wysocki

PM: QoS: Invalidate frequency QoS requests after removal



Switching cpufreq drivers (or switching operation modes of the
intel_pstate driver from "active" to "passive" and vice versa)
does not work on some x86 systems with ACPI after commit
3000ce3c ("cpufreq: Use per-policy frequency QoS"), because
the ACPI _PPC and thermal code uses the same frequency QoS request
object for a given CPU every time a cpufreq driver is registered
and freq_qos_remove_request() does not invalidate the request after
removing it from its QoS list, so freq_qos_add_request() complains
and fails when that request is passed to it again.

Fix the issue by modifying freq_qos_remove_request() to clear the qos
and type fields of the frequency request pointed to by its argument
after removing it from its QoS list so as to invalidate it.

Fixes: 3000ce3c ("cpufreq: Use per-policy frequency QoS")
Reported-and-tested-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

parent af42d346

kernel/power/qos.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -814,6 +814,8 @@ EXPORT_SYMBOL_GPL(freq_qos_update_request);
		*/
		int freq_qos_remove_request(struct freq_qos_request *req)
		{
		int ret;

		if (!req)
		return -EINVAL;

		@@ -821,7 +823,11 @@ int freq_qos_remove_request(struct freq_qos_request *req)
		"%s() called for unknown object\n", __func__))
		return -EINVAL;

		return freq_qos_apply(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
		ret = freq_qos_apply(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
		req->qos = NULL;
		req->type = 0;

		return ret;
		}
		EXPORT_SYMBOL_GPL(freq_qos_remove_request);

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