Re: [Intel-wired-lan] [PATCH] igc: fix netdev not re-attached after resume if interface is down

["Ruinskiy, Dima" <dima.ruinskiy@intel.com>]

On 23/07/2026 12:18, Loktionov, Aleksandr wrote:
> 
> 
>> -----Original Message-----
>> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf
>> Of Philipp David via Intel-wired-lan
>> Sent: Friday, July 17, 2026 11:22 AM
>> To: intel-wired-lan@lists.osuosl.org; netdev@vger.kernel.org
>> Cc: Nguyen, Anthony L <anthony.l.nguyen@intel.com>; Kitszel,
>> Przemyslaw <przemyslaw.kitszel@intel.com>; Andrew Lunn
>> <andrew+netdev@lunn.ch>; David S . Miller <davem@davemloft.net>; Eric
>> Dumazet <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo
>> Abeni <pabeni@redhat.com>; Philipp David <pd-lkml@3b.pm>;
>> stable@vger.kernel.org
>> Subject: [Intel-wired-lan] [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.
>>
>> Fixes: 6f31d6b643a3 ("igc: Refactor runtime power management flow")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Philipp David <pd-lkml@3b.pm>
>> ---
>>   drivers/net/ethernet/intel/igc/igc_main.c | 8 +++++---
>>   1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/intel/igc/igc_main.c
>> b/drivers/net/ethernet/intel/igc/igc_main.c
>> index 2c9e2dfd8499..e777c2df0b73 100644
>> --- a/drivers/net/ethernet/intel/igc/igc_main.c
>> +++ b/drivers/net/ethernet/intel/igc/igc_main.c
>> @@ -7586,11 +7586,13 @@ 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)
>> --
>> 2.54.0
> 
> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Reviewed-by: Dima Ruinskiy <dima.ruinskiy@intel.com>