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authorRafael J. Wysocki <rjw@sisk.pl>2012-05-07 22:00:59 +0200
committerRafael J. Wysocki <rjw@sisk.pl>2012-05-11 21:11:44 +0200
commitb723b0eb91e08a0ee9a401c0b22c0d52966d9daa (patch)
tree5730adb87db4c0d8cabec414495a401bcb421cec /drivers/base
parent4fcac10d28e7a046120b51a106b19082d2e57401 (diff)
PM / Domains: Fix computation of maximum domain off time
The default domain power off governor function for generic PM domains, default_power_down_ok(), may violate subdomain maximum off time limit by allowing the master domain to be off for too long. Namely, it only finds the minium of all device maximum off times over the domain's devices and uses that to compute the domain's maximum off time, but it should do the same for the subdomains. Fix this problem by modifying default_power_down_ok() to compute the given domain's maximum off time as the difference between the minimum off time over all devices and subdomains in the domain and its power on latency. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/power/domain_governor.c23
1 files changed, 12 insertions, 11 deletions
diff --git a/drivers/base/power/domain_governor.c b/drivers/base/power/domain_governor.c
index 3a5c5346bc4..28dee3053f1 100644
--- a/drivers/base/power/domain_governor.c
+++ b/drivers/base/power/domain_governor.c
@@ -105,7 +105,7 @@ static bool default_power_down_ok(struct dev_pm_domain *pd)
struct generic_pm_domain *genpd = pd_to_genpd(pd);
struct gpd_link *link;
struct pm_domain_data *pdd;
- s64 min_dev_off_time_ns;
+ s64 min_off_time_ns;
s64 off_on_time_ns;
if (genpd->max_off_time_changed) {
@@ -142,6 +142,7 @@ static bool default_power_down_ok(struct dev_pm_domain *pd)
to_gpd_data(pdd)->td.save_state_latency_ns;
}
+ min_off_time_ns = -1;
/*
* Check if subdomains can be off for enough time.
*
@@ -161,12 +162,14 @@ static bool default_power_down_ok(struct dev_pm_domain *pd)
*/
if (sd_max_off_ns <= off_on_time_ns)
return false;
+
+ if (min_off_time_ns > sd_max_off_ns || min_off_time_ns < 0)
+ min_off_time_ns = sd_max_off_ns;
}
/*
* Check if the devices in the domain can be off enough time.
*/
- min_dev_off_time_ns = -1;
list_for_each_entry(pdd, &genpd->dev_list, list_node) {
struct gpd_timing_data *td;
s64 constraint_ns;
@@ -197,9 +200,8 @@ static bool default_power_down_ok(struct dev_pm_domain *pd)
if (constraint_ns <= off_on_time_ns)
return false;
- if (min_dev_off_time_ns > constraint_ns
- || min_dev_off_time_ns < 0)
- min_dev_off_time_ns = constraint_ns;
+ if (min_off_time_ns > constraint_ns || min_off_time_ns < 0)
+ min_off_time_ns = constraint_ns;
}
genpd->cached_power_down_ok = true;
@@ -209,16 +211,15 @@ static bool default_power_down_ok(struct dev_pm_domain *pd)
* latency constraints, so the domain can spend arbitrary time in the
* "off" state.
*/
- if (min_dev_off_time_ns < 0)
+ if (min_off_time_ns < 0)
return true;
/*
- * The difference between the computed minimum device off time and the
- * time needed to turn the domain on is the maximum theoretical time
- * this domain can spend in the "off" state.
+ * The difference between the computed minimum subdomain or device off
+ * time and the time needed to turn the domain on is the maximum
+ * theoretical time this domain can spend in the "off" state.
*/
- genpd->max_off_time_ns = min_dev_off_time_ns -
- genpd->power_on_latency_ns;
+ genpd->max_off_time_ns = min_off_time_ns - genpd->power_on_latency_ns;
return true;
}