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

> -----Original Message-----
> From: Intel-wired-lan <[email protected]> On Behalf
> Of Philipp David via Intel-wired-lan
> Sent: Friday, July 17, 2026 11:22 AM
> To: [email protected]; [email protected]
> Cc: Nguyen, Anthony L <[email protected]>; Kitszel,
> Przemyslaw <[email protected]>; Andrew Lunn
> <[email protected]>; David S . Miller <[email protected]>; Eric
> Dumazet <[email protected]>; Jakub Kicinski <[email protected]>; Paolo
> Abeni <[email protected]>; Philipp David <[email protected]>;
> [email protected]
> 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: [email protected]
> Signed-off-by: Philipp David <[email protected]>
> ---
>  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 <[email protected]>