From: Rafael J. Wysocki rafael.j.wysocki@intel.com
commit 99387b016022c29234c4ebf9abd34358c6e56532 upstream.
Modify acpi_processor_get_platform_limit() to avoid updating its frequency QoS request when the _PPC return value has not changed by comparing that value to the previous _PPC return value stored in the performance_platform_limit field of the struct acpi_processor corresponding to the given CPU.
While at it, do the _PPC return value check against the state count earlier, to avoid setting performance_platform_limit to an invalid value, and make acpi_processor_ppc_init() use FREQ_QOS_MAX_DEFAULT_VALUE as the "no limit" frequency QoS for consistency.
Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Tested-by: Hagar Hemdan hagarhem@amazon.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/acpi/processor_perflib.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)
--- a/drivers/acpi/processor_perflib.c +++ b/drivers/acpi/processor_perflib.c @@ -76,13 +76,16 @@ static int acpi_processor_get_platform_l
index = ppc;
+ if (pr->performance_platform_limit == index || + ppc >= pr->performance->state_count) + return 0; + pr_debug("CPU %d: _PPC is %d - frequency %s limited\n", pr->id, index, index ? "is" : "is not");
pr->performance_platform_limit = index;
- if (ppc >= pr->performance->state_count || - unlikely(!freq_qos_request_active(&pr->perflib_req))) + if (unlikely(!freq_qos_request_active(&pr->perflib_req))) return 0;
/* @@ -177,9 +180,16 @@ void acpi_processor_ppc_init(struct cpuf if (!pr) continue;
+ /* + * Reset performance_platform_limit in case there is a stale + * value in it, so as to make it match the "no limit" QoS value + * below. + */ + pr->performance_platform_limit = 0; + ret = freq_qos_add_request(&policy->constraints, - &pr->perflib_req, - FREQ_QOS_MAX, INT_MAX); + &pr->perflib_req, FREQ_QOS_MAX, + FREQ_QOS_MAX_DEFAULT_VALUE); if (ret < 0) pr_err("Failed to add freq constraint for CPU%d (%d)\n", cpu, ret);