From: Ulf Hansson <ulf.hansson@linaro.org>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
linux-pm@vger.kernel.org
Cc: Geert Uytterhoeven <geert+renesas@glider.be>,
Kevin Hilman <khilman@linaro.org>,
Tomasz Figa <tomasz.figa@gmail.com>,
Philipp Zabel <philipp.zabel@gmail.com>,
Russell King <linux@arm.linux.org.uk>,
Mark Brown <broonie@kernel.org>, Wolfram Sang <wsa@the-dreams.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Jack Dai <jack.dai@rock-chips.com>,
Jinkun Hong <jinkun.hong@rock-chips.com>,
Ulf Hansson <ulf.hansson@linaro.org>
Subject: [PATCH 4/4] PM / Domains: Enforce PM domains to stay powered during boot
Date: Tue, 30 Sep 2014 14:43:53 +0200 [thread overview]
Message-ID: <1412081033-8136-5-git-send-email-ulf.hansson@linaro.org> (raw)
In-Reply-To: <1412081033-8136-1-git-send-email-ulf.hansson@linaro.org>
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 <ulf.hansson@linaro.org>
---
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
next prev parent reply other threads:[~2014-09-30 12:44 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-30 12:43 [PATCH 0/4] PM / Domains: Fix race conditions during boot Ulf Hansson
2014-09-30 12:43 ` [PATCH 1/4] PM / Domains: Remove pm_genpd_dev_need_restore() API Ulf Hansson
2014-09-30 13:21 ` Geert Uytterhoeven
2014-09-30 18:07 ` Kevin Hilman
2014-09-30 12:43 ` [PATCH 2/4] ARM: exynos: Ensure PM domains are powered at initialization Ulf Hansson
2014-09-30 18:33 ` Kevin Hilman
2014-10-01 11:23 ` Tomasz Figa
2014-10-01 12:45 ` Ulf Hansson
2014-09-30 12:43 ` [PATCH 3/4] PM / Domains: Expect PM domains being " Ulf Hansson
2014-09-30 13:24 ` Geert Uytterhoeven
2014-09-30 18:21 ` Kevin Hilman
2014-10-01 11:09 ` Ulf Hansson
2014-09-30 18:30 ` Kevin Hilman
2014-10-01 10:47 ` Ulf Hansson
2014-09-30 12:43 ` Ulf Hansson [this message]
2014-09-30 20:08 ` [PATCH 0/4] PM / Domains: Fix race conditions during boot Rafael J. Wysocki
2014-10-01 7:35 ` Ulf Hansson
2014-10-01 20:31 ` Rafael J. Wysocki
2014-10-02 9:28 ` Ulf Hansson
2014-10-02 10:07 ` Ulf Hansson
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