netdev - Re: [PATCH V3 net] net: stmmac: fix MAC WoL unwork if PHY doesn't support WoL

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Date:   Wed, 28 Apr 2021 14:26:30 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Joakim Zhang <qiangqing.zhang@....com>
Cc:     peppe.cavallaro@...com, alexandre.torgue@...com,
        joabreu@...opsys.com, davem@...emloft.net, kuba@...nel.org,
        f.fainelli@...il.com, Jisheng.Zhang@...aptics.com,
        netdev@...r.kernel.org, linux-imx@....com
Subject: Re: [PATCH V3 net] net: stmmac: fix MAC WoL unwork if PHY doesn't
 support WoL

>  static int stmmac_set_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
>  {
>  	struct stmmac_priv *priv = netdev_priv(dev);
> -	u32 support = WAKE_MAGIC | WAKE_UCAST;
> +	struct ethtool_wolinfo wol_phy = { .cmd = ETHTOOL_GWOL };
> +	u32 support = WAKE_MAGIC | WAKE_UCAST | WAKE_MAGICSECURE | WAKE_BCAST;

Reverse christmass tree please.

>  
> -	if (!device_can_wakeup(priv->device))
> -		return -EOPNOTSUPP;
> +	if (wol->wolopts & ~support)
> +		return -EINVAL;

Maybe -EOPNOTSUPP would be better.

>  
> -	if (!priv->plat->pmt) {
> +	/* First check if can WoL from PHY */
> +	phylink_ethtool_get_wol(priv->phylink, &wol_phy);

This could return an error. In which case, you probably should not
trust wol_phy.

> +	if (wol->wolopts & wol_phy.supported) {

This returns true if the PHY supports one or more of the requested WoL
sources.

>  		int ret = phylink_ethtool_set_wol(priv->phylink, wol);

and here you request the PHY to enable all the requested WoL
sources. If it only supports a subset, it is likely to return
-EOPNOTSUPP, or -EINVAL, and do nothing. So here you only want to
enable those sources the PHY actually supports. And let the MAC
implement the rest.

	  Andrew