lkml.org 
[lkml]   [2018]   [Jun]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] PM / core: Fix supplier device runtime PM usage counter imbalance
Date
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

If a device link is added via device_link_add() by the driver of the
link's consumer device, the supplier's runtime PM usage counter is
going to be dropped by the pm_runtime_put_suppliers() call in
driver_probe_device(). However, in that case it is not incremented
unless the supplier driver is already present and the link is not
stateless. That leads to a runtime PM usage counter imbalance for
the supplier device in a few cases.

To prevent that from happening, bump up the supplier runtime
PM usage counter in device_link_add() for all links with the
DL_FLAG_PM_RUNTIME flag set that are added at the consumer probe
time. Use pm_runtime_get_noresume() for that as the callers of
device_link_add() who want the supplier to be resumed by it should
pass DL_FLAG_RPM_ACTIVE in flags to it anyway.

Fixes: 21d5c57b3726 (PM / runtime: Use device links)
Reported-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

This is a replacement for commit 1e8378619841 (PM / runtime: Fixup
reference counting of device link suppliers at probe) that is going
to be reverted.

---
drivers/base/core.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)

Index: linux-pm/drivers/base/core.c
===================================================================
--- linux-pm.orig/drivers/base/core.c
+++ linux-pm/drivers/base/core.c
@@ -216,6 +216,13 @@ struct device_link *device_link_add(stru
link->rpm_active = true;
}
pm_runtime_new_link(consumer);
+ /*
+ * If the link is being added by the consumer driver at probe
+ * time, balance the decrementation of the supplier's runtime PM
+ * usage counter after consumer probe in driver_probe_device().
+ */
+ if (consumer->links.status == DL_DEV_PROBING)
+ pm_runtime_get_noresume(supplier);
}
get_device(supplier);
link->supplier = supplier;
@@ -234,14 +241,6 @@ struct device_link *device_link_add(stru
case DL_DEV_DRIVER_BOUND:
switch (consumer->links.status) {
case DL_DEV_PROBING:
- /*
- * Balance the decrementation of the supplier's
- * runtime PM usage counter after consumer probe
- * in driver_probe_device().
- */
- if (flags & DL_FLAG_PM_RUNTIME)
- pm_runtime_get_sync(supplier);
-
link->status = DL_STATE_CONSUMER_PROBE;
break;
case DL_DEV_DRIVER_BOUND:
\
 
 \ /
  Last update: 2018-06-12 13:02    [W:0.075 / U:0.944 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site