This patch catches the cases where dev_get_performance_state() callback is implemented for a genpd, but none of its masters or their masters (and so on) have implemented genpd_set_performance_state() callback.
The internal performance state routines don't return 0 anymore for success, rather they return count of the domains whose performance state is updated and the top level routine checks for that. A zero value there would indicate that the genpd_set_performance_state() callbacks are missing in the master hierarchy of the device. This adds very little burden on the API and can be pretty useful. Tested-by: Rajendra Nayak <[email protected]> Signed-off-by: Viresh Kumar <[email protected]> --- drivers/base/power/domain.c | 40 +++++++++++++++++++++++++++------------- 1 file changed, 27 insertions(+), 13 deletions(-) diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c index 5f50d5295cd4..0922679c1d43 100644 --- a/drivers/base/power/domain.c +++ b/drivers/base/power/domain.c @@ -264,18 +264,20 @@ EXPORT_SYMBOL_GPL(dev_pm_genpd_has_performance_state); static int _genpd_reeval_performance_state(struct generic_pm_domain *genpd, int state, int depth); -/* Returns -ve errors or 0 on success */ +/* Returns -ve errors or number of domains whose performance is set */ static int _genpd_set_performance_state(struct generic_pm_domain *genpd, int state, int depth) { struct generic_pm_domain *master; struct gpd_link *link; - int prev = genpd->performance_state, ret; + int prev = genpd->performance_state, ret, count = 0; if (genpd->genpd_set_performance_state) { ret = genpd->genpd_set_performance_state(genpd, state); if (ret) return ret; + + count = 1; } /* Propagate to masters of genpd */ @@ -286,13 +288,15 @@ static int _genpd_set_performance_state(struct generic_pm_domain *genpd, link->performance_state = state; ret = _genpd_reeval_performance_state(master, state, depth + 1); - if (ret) + if (ret < 0) link->performance_state = prev; genpd_unlock(master); - if (ret) + if (ret < 0) goto err; + + count += ret; } /* @@ -300,7 +304,7 @@ static int _genpd_set_performance_state(struct generic_pm_domain *genpd, * with those. */ genpd->performance_state = state; - return 0; + return count; err: /* Encountered an error, lets rollback */ @@ -310,7 +314,7 @@ static int _genpd_set_performance_state(struct generic_pm_domain *genpd, genpd_lock_nested(master, depth + 1); link->performance_state = prev; - if (_genpd_reeval_performance_state(master, prev, depth + 1)) { + if (_genpd_reeval_performance_state(master, prev, depth + 1) < 0) { pr_err("%s: Failed to roll back to %d performance state\n", master->name, prev); } @@ -352,7 +356,7 @@ static int _genpd_set_performance_state(struct generic_pm_domain *genpd, * - The locks are always taken in bottom->up order, i.e. subdomain first, * followed by its masters. * - * Returns -ve errors or 0 on success. + * Returns -ve errors or number of domains whose performance is set. */ static int _genpd_reeval_performance_state(struct generic_pm_domain *genpd, int state, int depth) @@ -361,9 +365,14 @@ static int _genpd_reeval_performance_state(struct generic_pm_domain *genpd, struct pm_domain_data *pdd; struct gpd_link *link; - /* New requested state is same as Max requested state */ - if (state == genpd->performance_state) - return 0; + if (state == genpd->performance_state) { + /* + * New requested state is same as Max requested state, return 1 + * to distinguish from the case where none of the masters have + * set their genpd_set_performance_state() callback. + */ + return 1; + } /* New requested state is higher than Max requested state */ if (state > genpd->performance_state) @@ -451,7 +460,7 @@ int dev_pm_genpd_update_performance_state(struct device *dev, } ret = _genpd_reeval_performance_state(genpd, state, 0); - if (!ret) { + if (ret > 0) { /* * Since we are passing "state" to * _genpd_reeval_performance_state() as well, we don't need to @@ -460,6 +469,11 @@ int dev_pm_genpd_update_performance_state(struct device *dev, * state of master domain is updated. */ __genpd_dev_update_performance_state(dev, state); + ret = 0; + } else { + WARN(!ret, "%s: None of %s and its masters have provided genpd_set_performance_state()\n", + __func__, genpd->name); + ret = -ENODEV; } unlock: @@ -478,7 +492,7 @@ static int _genpd_on_update_performance_state(struct generic_pm_domain *genpd, return 0; ret = _genpd_set_performance_state(genpd, prev, depth); - if (ret) { + if (ret < 0) { pr_err("%s: Failed to restore performance state to %d (%d)\n", genpd->name, prev, ret); } else { @@ -497,7 +511,7 @@ static void _genpd_off_update_performance_state(struct generic_pm_domain *genpd, return; ret = _genpd_set_performance_state(genpd, 0, depth); - if (ret) { + if (ret < 0) { pr_err("%s: Failed to set performance state to 0 (%d)\n", genpd->name, ret); } else { -- 2.13.0.71.gd7076ec9c9cb
