From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
kernel/power/qos.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
Index: linux-pm/kernel/power/qos.c
===================================================================
--- linux-pm.orig/kernel/power/qos.c
+++ linux-pm/kernel/power/qos.c
@@ -814,6 +814,8 @@ EXPORT_SYMBOL_GPL(freq_qos_update_reques
*/
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_
"%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);
