When there are more than one device in a PM domain these will obviously be probed at different times. Depending on timing and the implemented support for runtime PM in a driver/subsystem, genpd may be advised to power off a PM domain after a successful probe sequence.
Ideally we should have relied on the driver/subsystem, through runtime PM, to bring their device's PM domain into powered state prior doing probing if such requirement exist. Since this is not a common practice by drivers/subsystems, enforcing such a change doesn't seem viable. Instead, let's improve the situation, by preventing genpd from powering off any of the PM domains until late_init. At that point genpd already tries to power off unused PM domains, so it seems like a decent match. Cases which can't be covered within the window of until late_init needs to be adressed separately and likely through a more common long term solution. Signed-off-by: Ulf Hansson <[email protected]> --- drivers/base/power/domain.c | 17 ++++++++++++++++- include/linux/pm_domain.h | 1 + 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c index cfb76e8..3dbadfd 100644 --- a/drivers/base/power/domain.c +++ b/drivers/base/power/domain.c @@ -451,10 +451,12 @@ static int pm_genpd_poweroff(struct generic_pm_domain *genpd) * (2) The domain is waiting for its master to power up. * (3) One of the domain's devices is being resumed right now. * (4) System suspend is in progress. + * (5) late_init hasn't completed to allow it. */ if (genpd->status == GPD_STATE_POWER_OFF || genpd->status == GPD_STATE_WAIT_MASTER - || genpd->resume_count > 0 || genpd->prepared_count > 0) + || genpd->resume_count > 0 || genpd->prepared_count > 0 + || genpd->keep_power) return 0; if (atomic_read(&genpd->sd_count) > 0) @@ -724,6 +726,18 @@ void pm_genpd_poweroff_unused(void) static int __init genpd_poweroff_unused(void) { + struct generic_pm_domain *genpd; + + mutex_lock(&gpd_list_lock); + + list_for_each_entry(genpd, &gpd_list, gpd_list_node) { + genpd_acquire_lock(genpd); + genpd->keep_power = false; + genpd_release_lock(genpd); + } + + mutex_unlock(&gpd_list_lock); + pm_genpd_poweroff_unused(); return 0; } @@ -1854,6 +1868,7 @@ void pm_genpd_init(struct generic_pm_domain *genpd, genpd->status = GPD_STATE_ACTIVE; init_waitqueue_head(&genpd->status_wait_queue); genpd->poweroff_task = NULL; + genpd->keep_power = true; genpd->resume_count = 0; genpd->device_count = 0; genpd->max_off_time_ns = -1; diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h index ad4aa87..d87ef6a 100644 --- a/include/linux/pm_domain.h +++ b/include/linux/pm_domain.h @@ -58,6 +58,7 @@ struct generic_pm_domain { enum gpd_status status; /* Current state of the domain */ wait_queue_head_t status_wait_queue; struct task_struct *poweroff_task; /* Powering off task */ + bool keep_power; /* Flag to keep power until late_init */ unsigned int resume_count; /* Number of devices being resumed */ unsigned int device_count; /* Number of devices */ unsigned int suspended_count; /* System suspend device counter */ -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
