PM / Domains: defer dev_pm_domain_set() until genpd->attach_dev succeeds if present

If the genpd->attach_dev or genpd->power_on fails, genpd_dev_pm_attach
may return -EPROBE_DEFER initially. However genpd_alloc_dev_data sets
the PM domain for the device unconditionally.

When subsequent attempts are made to call genpd_dev_pm_attach, it may
return -EEXISTS checking dev->pm_domain without re-attempting to call
attach_dev or power_on.

platform_drv_probe then attempts to call drv->probe as the return value
-EEXIST != -EPROBE_DEFER, which may end up in a situation where the
device is accessed without it's power domain switched on.

Fixes: f104e1e5ef57 (PM / Domains: Re-order initialization of generic_pm_domain_data)
Cc: 4.4+ <stable@vger.kernel.org> # v4.4+
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 2ac9062..91ba826 100644 (file)
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -1222,8 +1222,6 @@ static struct generic_pm_domain_data *genpd_alloc_dev_data(struct device *dev,
 
        spin_unlock_irq(&dev->power.lock);
 
-       dev_pm_domain_set(dev, &genpd->domain);
-
        return gpd_data;
 
  err_free:
@@ -1237,8 +1235,6 @@ static struct generic_pm_domain_data *genpd_alloc_dev_data(struct device *dev,
 static void genpd_free_dev_data(struct device *dev,
                                struct generic_pm_domain_data *gpd_data)
 {
-       dev_pm_domain_set(dev, NULL);
-
        spin_lock_irq(&dev->power.lock);
 
        dev->power.subsys_data->domain_data = NULL;
@@ -1275,6 +1271,8 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev,
        if (ret)
                goto out;
 
+       dev_pm_domain_set(dev, &genpd->domain);
+
        genpd->device_count++;
        genpd->max_off_time_changed = true;
 
@@ -1336,6 +1334,8 @@ static int genpd_remove_device(struct generic_pm_domain *genpd,
        if (genpd->detach_dev)
                genpd->detach_dev(genpd, dev);
 
+       dev_pm_domain_set(dev, NULL);
+
        list_del_init(&pdd->list_node);
 
        genpd_unlock(genpd);