[RFC][PATCH] PM / Domains: Return -EPROBE_DEFER if we fail to init or turn-on domain
From: Jon Hunter <jonathanh@nvidia.com>
Date: 2015-06-18 17:52:53
Subsystem:
driver core, kobjects, debugfs and sysfs, hibernation (aka software suspend, aka swsusp), power management core, suspend to ram, the rest · Maintainers:
Greg Kroah-Hartman, "Rafael J. Wysocki", Danilo Krummrich, Linus Torvalds
When a device is probed, the function dev_pm_domain_attach() is called to see if there is a power-domain that is associated with the device and needs to be turned on. If dev_pm_domain_attach() does not return -EPROBE_DEFER then the device will be probed. For devices using genpd, dev_pm_domain_attach() will call genpd_dev_pm_attach(). If genpd_dev_pm_attach() does not find a power domain associated with the device then it returns an error code not equal to -EPROBE_DEFER to allow the device to be probed. However, if genpd_dev_pm_attach() does find a power-domain that is associated with the device, then it does not return -EPROBE_DEFER on failure and hence the device will still be probed. Furthermore, genpd_dev_pm_attach() does not check the error code returned by pm_genpd_poweron() to see if the power-domain was turned on successfully. Signed-off-by: Jon Hunter <jonathanh@nvidia.com> --- FWICT, it seems to me that we would not want to probe the device if there is a power-domain associated but we fail to initialise it or it fails to turn on. Of course I could be wrong here and so please let me know if my interpretation is utterly flawed in someway ;-) drivers/base/power/domain.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index cdd547bd67df..c69e87ccb150 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c@@ -2177,7 +2177,10 @@ static void genpd_dev_pm_sync(struct device *dev) * Both generic and legacy Samsung-specific DT bindings are supported to keep * backwards compatibility with existing DTBs. * - * Returns 0 on successfully attached PM domain or negative error code. + * Returns 0 on successfully attached PM domain or negative error code. Note + * that if a power-domain exists for the device, but it cannot be found or + * turned on, then return -EPROBE_DEFER to ensure that the device is not + * probed and to re-try again later. */ int genpd_dev_pm_attach(struct device *dev) {
@@ -2213,7 +2216,7 @@ int genpd_dev_pm_attach(struct device *dev) dev_dbg(dev, "%s() failed to find PM domain: %ld\n", __func__, PTR_ERR(pd)); of_node_put(dev->of_node); - return PTR_ERR(pd); + return -EPROBE_DEFER; } dev_dbg(dev, "adding to PM domain %s\n", pd->name);
@@ -2229,14 +2232,15 @@ int genpd_dev_pm_attach(struct device *dev) dev_err(dev, "failed to add to PM domain %s: %d", pd->name, ret); of_node_put(dev->of_node); - return ret; + goto out; } dev->pm_domain->detach = genpd_dev_pm_detach; dev->pm_domain->sync = genpd_dev_pm_sync; - pm_genpd_poweron(pd); + ret = pm_genpd_poweron(pd); - return 0; +out: + return ret ? -EPROBE_DEFER : 0; } EXPORT_SYMBOL_GPL(genpd_dev_pm_attach); #endif /* CONFIG_PM_GENERIC_DOMAINS_OF */
--
2.1.4