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
3000ce3c52f8 ("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: 3000ce3c52f8 ("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>

diff --git a/kernel/power/qos.c b/kernel/power/qos.c
index 04e83fd..a45cba7 100644 (file)
--- a/kernel/power/qos.c
+++ b/kernel/power/qos.c
@@ -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);