Re: [PATCH net 1/2] net: stmmac: propagate platform mac_finish errors

[Mohd Ayaan Anwar <mohd.anwar@oss.qualcomm.com>]

On Wed, Sep 16, 2026 at 08:39:49PM +1000, Thomas Karpiniec wrote:
> From: Thomas Karpiniec <tom@wendy.sh>
> 
> stmmac_mac_finish() discards the platform callback's return value and
> always reports success to phylink. For example, the Qualcomm ETHQOS
> callback can return an error from phy_set_mode_ext() if SerDes
> configuration fails. Phylink then treats the interface as successfully
> configured and can report carrier even though the SerDes is not ready.
> 
> Return the platform callback's result so that phylink can report the
> failure and keep the link down until a subsequent configuration succeeds.
> Keep returning zero when no platform callback is installed.
> 
> Fixes: e654cfc718d4 ("net: stmmac: configure SerDes on mac_finish")
> Cc: stable@vger.kernel.org
> Assisted-by: LLM sparse
> Signed-off-by: Thomas Karpiniec <tom@wendy.sh>
> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 1fb5f804ea23..1350e92943ac 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -1048,8 +1048,8 @@ static int stmmac_mac_finish(struct phylink_config *config, unsigned int mode,
>  	struct stmmac_priv *priv = netdev_priv(ndev);
>  
>  	if (priv->plat->mac_finish)
> -		priv->plat->mac_finish(ndev, priv->plat->bsp_priv, mode,
> -				       interface);
> +		return priv->plat->mac_finish(ndev, priv->plat->bsp_priv, mode,
> +					     interface);
>  
>  	return 0;
>  }

Just curious, are you trying to resolve the issue where an interface
gets created depite:
  qcom-dwmac-sgmii-phy 8909000.phy: QSERDES_COM_C_READY_STATUS timed-out
  qcom-ethqos 23040000.ethernet eth0: __stmmac_open: Serdes powerup failed
in dmesg?

Anyways, the change looks reasonable to me:

Acked-by: Mohd Ayaan Anwar <mohd.anwar@oss.qualcomm.com>

	Ayaan