FAILED: patch "[PATCH] igc: fix netdev not re-attached after resume if interface is" failed to apply to 6.12-stable tree

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x b0ce5fd9fabe7c79463cf4602217d4dfeff5b1fd
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026081708-decrease-satchel-2a72@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b0ce5fd9fabe7c79463cf4602217d4dfeff5b1fd Mon Sep 17 00:00:00 2001
From: Philipp David <[email protected]>
Date: Tue, 4 Aug 2026 15:22:03 -0700
Subject: [PATCH] igc: fix netdev not re-attached after resume if interface is
down

__igc_resume() calls netif_device_attach() only inside the netif_running() branch, so an interface that was down during suspend is never re-attached on resume. It then stays in the not-present state that __igc_shutdown() set via netif_device_detach(): ethtool reports ENODEV and every attempt to bring the interface up fails the netif_device_present() check in __dev_open() with -ENODEV, silently, since __igc_resume() returns 0. Only reloading the driver recovers the device.

This is easy to hit in practice because NetworkManager brings managed interfaces down before sleep unless Wake-on-LAN is configured, making the adapter unusable after every suspend/resume cycle with WoL disabled.

Re-attach the netdev on every successful resume, as igb and e1000e do.

index 16fcc8cf6191..39043d8ca1bf 100644
@@ -7585,11 +7585,13 @@ static int __igc_resume(struct device *dev, bool rpm)
 		err = __igc_open(netdev, true);
 		if (!rpm)
 			rtnl_unlock();
-		if (!err)
-			netif_device_attach(netdev);
+		if (err)
+			return err;
 	}
 
-	return err;
+	netif_device_attach(netdev);
+
+	return 0;
 }
 
 static int igc_resume(struct device *dev)

__igc_resume() calls netif_device_attach() only inside the netif_running() branch, so an interface that was down during suspend is never re-attached on resume. It then stays in the not-present state that __igc_shutdown() set via netif_device_detach(): ethtool reports ENODEV and every attempt to bring the interface up fails the netif_device_present() check in __dev_open() with -ENODEV, silently, since __igc_resume() returns 0. Only reloading the driver recovers the device.

This is easy to hit in practice because NetworkManager brings managed interfaces down before sleep unless Wake-on-LAN is configured, making the adapter unusable after every suspend/resume cycle with WoL disabled.

Re-attach the netdev on every successful resume, as igb and e1000e do.

---
Conflict resolved cleanly using mergiraf. Backport tested on I225-V hardware, suspend with WoL and suspend without WoL both bringing up interface again after resume.

 drivers/net/ethernet/intel/igc/igc_main.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

index 6fcf4fd7ee19..ecc33f797e37 100644
@@ -7405,11 +7405,13 @@ static int igc_resume(struct device *dev)
 
 	if (netif_running(netdev)) {
 		err = __igc_open(netdev, true);
-		if (!err)
-			netif_device_attach(netdev);
+		if (err)
+			return err;
 	}
 
-	return err;
+	netif_device_attach(netdev);
+
+	return 0;
 }
 
 static int igc_runtime_resume(struct device *dev)

2.55.0

Queued for 6.12, thanks.

Thanks,
Sasha