[PATCH] PM: QoS: Invalidate frequency QoS requests after removal

[PATCH] PM: QoS: Invalidate frequency QoS requests after removal

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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>
---
 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);
 

Re: [PATCH] PM: QoS: Invalidate frequency QoS requests after removal

[Viresh Kumar]

On 20-11-19, 10:33, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> 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>
> ---
>  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);

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh