Hi,
On 10/27/2016 06:23 AM, Ulf Hansson wrote:
The smsc911c driver puts its device into low power state when entering
system suspend. Although it doesn't update the device's runtime PM status
to RPM_SUSPENDED, which causes problems for a parent device.
In particular, when the runtime PM status of the parent is requested to be
updated to RPM_SUSPENDED, the runtime PM core prevent this, because it's
forbidden to runtime suspend a device, which has an active child.
Fix this by updating the runtime PM status of the smsc911x device to
RPM_SUSPENDED during system suspend. In system resume, let's reverse that
action by runtime resuming the device and thus also the parent.
Signed-off-by: Ulf Hansson <ulf.hans...@linaro.org>
Tested-by: Geert Uytterhoeven <geert+rene...@glider.be>
Cc: Steve Glendinning <steve.glendinn...@shawell.net>
Fixes: 8b1107b85efd ("PM / Runtime: Don't allow to suspend a device with an active
child")
---
Note that the commit this change fixes is currently queued for 4.10 via
Rafael's linux-pm tree. So this fix should go via that tree as well.
---
drivers/net/ethernet/smsc/smsc911x.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/net/ethernet/smsc/smsc911x.c
b/drivers/net/ethernet/smsc/smsc911x.c
index e9b8579..65fca9c 100644
--- a/drivers/net/ethernet/smsc/smsc911x.c
+++ b/drivers/net/ethernet/smsc/smsc911x.c
@@ -2584,6 +2584,9 @@ static int smsc911x_suspend(struct device *dev)
PMT_CTRL_PM_MODE_D1_ | PMT_CTRL_WOL_EN_ |
PMT_CTRL_ED_EN_ | PMT_CTRL_PME_EN_);
+ pm_runtime_disable(dev);
+ pm_runtime_set_suspended(dev);
+
return 0;
}
@@ -2593,6 +2596,9 @@ static int smsc911x_resume(struct device *dev)
struct smsc911x_data *pdata = netdev_priv(ndev);
unsigned int to = 100;
+ pm_runtime_enable(dev);
+ pm_runtime_resume(dev);
+
/* Note 3.11 from the datasheet:
* "When the LAN9220 is in a power saving state, a write of any
* data to the BYTE_TEST register will wake-up the device."
This seems an unusual change/sequence. I thought a successful return
from the suspend callback would set the device state to suspended.
I just checked a few other ethernet drivers suspend/resume sequences and
directly calling the pm_runtime seems a little unusual. Most of the
other drivers are checking to see if the interface is running then doing
a netif_device_detach()/attach() sequence which is missing from this
drivers suspend/resume path. Could that be part of the problem?
Of course my knowledge of the power management system is a little thin
so I could be really off base.
