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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-10-23 17:35:19 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-10-27 18:47:40 +0100
commit1c534352f47fd83eb08075ac2474f707e74bf7f7 (patch)
tree8c931162140874a4d8549370207321e906d50f87 /include
parentdb865272d9c4687520dc29f77e701a1b2669872f (diff)
cpufreq: Introduce CPUFREQ_NEED_UPDATE_LIMITS driver flag
Generally, a cpufreq driver may need to update some internal upper and lower frequency boundaries on policy max and min changes, respectively, but currently this does not work if the target frequency does not change along with the policy limit. Namely, if the target frequency does not change along with the policy min or max, the "target_freq == policy->cur" check in __cpufreq_driver_target() prevents driver callbacks from being invoked and they do not even have a chance to update the corresponding internal boundary. This particularly affects the "powersave" and "performance" governors that always set the target frequency to one of the policy limits and it never changes when the other limit is updated. To allow cpufreq the drivers needing to update internal frequency boundaries on policy limits changes to avoid this issue, introduce a new driver flag, CPUFREQ_NEED_UPDATE_LIMITS, that (when set) will neutralize the check mentioned above. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/cpufreq.h10
1 files changed, 9 insertions, 1 deletions
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index fa37b1c66443..038ed83aab41 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -298,7 +298,7 @@ __ATTR(_name, 0644, show_##_name, store_##_name)
struct cpufreq_driver {
char name[CPUFREQ_NAME_LEN];
- u8 flags;
+ u16 flags;
void *driver_data;
/* needed by all drivers */
@@ -422,6 +422,14 @@ struct cpufreq_driver {
*/
#define CPUFREQ_IS_COOLING_DEV BIT(7)
+/*
+ * Set by drivers that need to update internale upper and lower boundaries along
+ * with the target frequency and so the core and governors should also invoke
+ * the diver if the target frequency does not change, but the policy min or max
+ * may have changed.
+ */
+#define CPUFREQ_NEED_UPDATE_LIMITS BIT(8)
+
int cpufreq_register_driver(struct cpufreq_driver *driver_data);
int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);

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