Re: [PATCH net-next 5/6] net: stmmac: move PHY handling out of __stmmac_open()/release()

[Alexander Stein <alexander.stein@ew.tq-group.com>]

Hi,

Am Dienstag, 23. September 2025, 13:26:19 CEST schrieb Russell King (Oracle):
> Move the PHY attachment/detachment from the network driver out of
> __stmmac_open() and __stmmac_release() into stmmac_open() and
> stmmac_release() where these actions will only happen when the
> interface is administratively brought up or down. It does not make
> sense to detach and re-attach the PHY during a change of MTU.

Sorry for coming up now. But I recently noticed this commit breaks changing
the MTU on i.MX8MP. Once I simply change the MTU I run into some DMA error:
$ ip link set dev end1 mtu 1400
imx-dwmac 30bf0000.ethernet end1: Register MEM_TYPE_PAGE_POOL RxQ-0
imx-dwmac 30bf0000.ethernet end1: Register MEM_TYPE_PAGE_POOL RxQ-1
imx-dwmac 30bf0000.ethernet end1: Register MEM_TYPE_PAGE_POOL RxQ-2
imx-dwmac 30bf0000.ethernet end1: Register MEM_TYPE_PAGE_POOL RxQ-3
imx-dwmac 30bf0000.ethernet end1: Register MEM_TYPE_PAGE_POOL RxQ-4
imx-dwmac 30bf0000.ethernet end1: Link is Down
imx-dwmac 30bf0000.ethernet end1: Failed to reset the dma
imx-dwmac 30bf0000.ethernet end1: stmmac_hw_setup: DMA engine initialization failed
imx-dwmac 30bf0000.ethernet end1: __stmmac_open: Hw setup failed
imx-dwmac 30bf0000.ethernet end1: failed reopening the interface after MTU change

Using the command above bisecting was straight forward.
For some reason detach and re-attaching the PHY seems necessary on this platform.
There already too much changes for simply reverting this commit.

Best regards,
Alexander

> 
> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
> ---
>  .../net/ethernet/stmicro/stmmac/stmmac_main.c | 29 +++++++++++--------
>  1 file changed, 17 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 4acd180d2da8..4844d563e291 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -3937,10 +3937,6 @@ static int __stmmac_open(struct net_device *dev,
>  	u32 chan;
>  	int ret;
>  
> -	ret = stmmac_init_phy(dev);
> -	if (ret)
> -		return ret;
> -
>  	for (int i = 0; i < MTL_MAX_TX_QUEUES; i++)
>  		if (priv->dma_conf.tx_queue[i].tbs & STMMAC_TBS_EN)
>  			dma_conf->tx_queue[i].tbs = priv->dma_conf.tx_queue[i].tbs;
> @@ -3990,7 +3986,6 @@ static int __stmmac_open(struct net_device *dev,
>  
>  	stmmac_release_ptp(priv);
>  init_error:
> -	phylink_disconnect_phy(priv->phylink);
>  	return ret;
>  }
>  
> @@ -4010,18 +4005,28 @@ static int stmmac_open(struct net_device *dev)
>  
>  	ret = pm_runtime_resume_and_get(priv->device);
>  	if (ret < 0)
> -		goto err;
> +		goto err_dma_resources;
> +
> +	ret = stmmac_init_phy(dev);
> +	if (ret)
> +		goto err_runtime_pm;
>  
>  	ret = __stmmac_open(dev, dma_conf);
> -	if (ret) {
> -		pm_runtime_put(priv->device);
> -err:
> -		free_dma_desc_resources(priv, dma_conf);
> -	}
> +	if (ret)
> +		goto err_disconnect_phy;
>  
>  	kfree(dma_conf);
>  
>  	return ret;
> +
> +err_disconnect_phy:
> +	phylink_disconnect_phy(priv->phylink);
> +err_runtime_pm:
> +	pm_runtime_put(priv->device);
> +err_dma_resources:
> +	free_dma_desc_resources(priv, dma_conf);
> +	kfree(dma_conf);
> +	return ret;
>  }
>  
>  static void __stmmac_release(struct net_device *dev)
> @@ -4038,7 +4043,6 @@ static void __stmmac_release(struct net_device *dev)
>  
>  	/* Stop and disconnect the PHY */
>  	phylink_stop(priv->phylink);
> -	phylink_disconnect_phy(priv->phylink);
>  
>  	stmmac_disable_all_queues(priv);
>  
> @@ -4078,6 +4082,7 @@ static int stmmac_release(struct net_device *dev)
>  
>  	__stmmac_release(dev);
>  
> +	phylink_disconnect_phy(priv->phylink);
>  	pm_runtime_put(priv->device);
>  
>  	return 0;
> 


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