[PATCH] powerpc/gianfar: fix ethernet cannot work after restoring from hibernation

we should make sure a ethernet has been taken down when system into hibernation
status. when the system restoring form hibernation, the ethernet cannot be
taken up.
eg:
~# ifconfig eth0 down
~# echo disk > /sys/power/state

hibernation restore

~# ifconfig eth0 up
SIOCSIFFLAGS: No such device

Signed-off-by: Wang Dongsheng <redacted>
---
 drivers/net/ethernet/freescale/gianfar.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c
index 4605f72..487b944 100644
--- a/drivers/net/ethernet/freescale/gianfar.c
+++ b/drivers/net/ethernet/freescale/gianfar.c

@@ -1345,8 +1345,11 @@ static int gfar_restore(struct device *dev)
 	struct gfar_private *priv = dev_get_drvdata(dev);
 	struct net_device *ndev = priv->ndev;
 
-	if (!netif_running(ndev))
+	if (!netif_running(ndev)) {
+		netif_device_attach(ndev);
+
 		return 0;
+	}
 
 	gfar_init_bds(ndev);
 	init_registers(ndev);

-- 
1.7.5.1

From: Wang Dongsheng <redacted>

If a gianfar ethernet device is down prior to hibernating a
system, it will no longer be present upon system restore.

For example:

	~# ifconfig eth0 down
	~# echo disk > /sys/power/state

	  <trigger a restore from hibernation>

	~# ifconfig eth0 up
	SIOCSIFFLAGS: No such device

This happens because the restore function bails out early upon
finding devices that were not up at hibernation.  In doing so,
it never gets to the netif_device_attach call at the end of
the restore function.  Adding the netif_device_attach as done
here also makes the gfar_restore code consistent with what is
done in the gfar_resume code.

Cc: Claudiu Manoil <redacted>
Signed-off-by: Wang Dongsheng <redacted>
Signed-off-by: Paul Gortmaker <redacted>
---
[v2: expand on details in commit log a bit more, to superceed
 v1 at http://patchwork.ozlabs.org/patch/197412/ ]

 drivers/net/ethernet/freescale/gianfar.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c
index 1d03dcd..19ac096 100644
--- a/drivers/net/ethernet/freescale/gianfar.c
+++ b/drivers/net/ethernet/freescale/gianfar.c

@@ -1353,8 +1353,11 @@ static int gfar_restore(struct device *dev)
 	struct gfar_private *priv = dev_get_drvdata(dev);
 	struct net_device *ndev = priv->ndev;
 
-	if (!netif_running(ndev))
+	if (!netif_running(ndev)) {
+		netif_device_attach(ndev);
+
 		return 0;
+	}
 
 	gfar_init_bds(ndev);
 	init_registers(ndev);

-- 
1.8.0

On 11/9/2012 4:43 PM, Paul Gortmaker wrote:

From: Wang Dongsheng <redacted>

If a gianfar ethernet device is down prior to hibernating a
system, it will no longer be present upon system restore.

For example:

	~# ifconfig eth0 down
	~# echo disk > /sys/power/state

	  <trigger a restore from hibernation>

	~# ifconfig eth0 up
	SIOCSIFFLAGS: No such device

This happens because the restore function bails out early upon
finding devices that were not up at hibernation.  In doing so,
it never gets to the netif_device_attach call at the end of
the restore function.  Adding the netif_device_attach as done
here also makes the gfar_restore code consistent with what is
done in the gfar_resume code.

Cc: Claudiu Manoil <redacted>

Hello Paul,

Thought I don't have the proper setup to test the hibernation feature,
I agree with this patch especially now that the description is much
clearer. I fully agree on the consistency argument b/w gfar_restore and
gfar_resume. (good observation)

Acked-by: Claudiu Manoil <redacted>

From: Paul Gortmaker <redacted>
Date: Fri,  9 Nov 2012 09:43:51 -0500

From: Wang Dongsheng <redacted>

If a gianfar ethernet device is down prior to hibernating a
system, it will no longer be present upon system restore.

For example:

	~# ifconfig eth0 down
	~# echo disk > /sys/power/state

	  <trigger a restore from hibernation>

	~# ifconfig eth0 up
	SIOCSIFFLAGS: No such device

This happens because the restore function bails out early upon
finding devices that were not up at hibernation.  In doing so,
it never gets to the netif_device_attach call at the end of
the restore function.  Adding the netif_device_attach as done
here also makes the gfar_restore code consistent with what is
done in the gfar_resume code.

Cc: Claudiu Manoil <redacted>
Signed-off-by: Wang Dongsheng <redacted>
Signed-off-by: Paul Gortmaker <redacted>

Applied, thanks.