On 20-11-19, 10:33, Rafael J. Wysocki wrote:
> 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);
Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
--
viresh
