Re: [PATCH v4 3/5] net: macb: fix macb_get/set_wol() when moving to phylink - Russell King

From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: nicolas.ferre@microchip.com
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>,
	f.fainelli@gmail.com, antoine.tenart@bootlin.com,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	"David S. Miller" <davem@davemloft.net>,
	harini.katakam@xilinx.com,
	Claudiu Beznea <claudiu.beznea@microchip.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v4 3/5] net: macb: fix macb_get/set_wol() when moving to phylink
Date: Wed, 13 May 2020 14:05:36 +0100	[thread overview]
Message-ID: <20200513130536.GI1551@shell.armlinux.org.uk> (raw)
In-Reply-To: <4aeebe901fde6db70a5ca12b10e793dd2ee6ce60.1588763703.git.nicolas.ferre@microchip.com>

On Wed, May 06, 2020 at 01:37:39PM +0200, nicolas.ferre@microchip.com wrote:
> From: Nicolas Ferre <nicolas.ferre@microchip.com>
> 
> Keep previous function goals and integrate phylink actions to them.
> 
> phylink_ethtool_get_wol() is not enough to figure out if Ethernet driver
> supports Wake-on-Lan.
> Initialization of "supported" and "wolopts" members is done in phylink
> function, no need to keep them in calling function.
> 
> phylink_ethtool_set_wol() return value is not enough to determine
> if WoL is enabled for the calling Ethernet driver. Call it first
> but don't rely on its return value as most of simple PHY drivers
> don't implement a set_wol() function.
> 
> Fixes: 7897b071ac3b ("net: macb: convert to phylink")
> Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
> Cc: Claudiu Beznea <claudiu.beznea@microchip.com>
> Cc: Harini Katakam <harini.katakam@xilinx.com>
> Cc: Antoine Tenart <antoine.tenart@bootlin.com>
> ---
>  drivers/net/ethernet/cadence/macb_main.c | 18 ++++++++++--------
>  1 file changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
> index 53e81ab048ae..24c044dc7fa0 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -2817,21 +2817,23 @@ static void macb_get_wol(struct net_device *netdev, struct ethtool_wolinfo *wol)
>  {
>  	struct macb *bp = netdev_priv(netdev);
>  
> -	wol->supported = 0;
> -	wol->wolopts = 0;
> -
> -	if (bp->wol & MACB_WOL_HAS_MAGIC_PACKET)
> +	if (bp->wol & MACB_WOL_HAS_MAGIC_PACKET) {
>  		phylink_ethtool_get_wol(bp->phylink, wol);
> +		wol->supported |= WAKE_MAGIC;
> +
> +		if (bp->wol & MACB_WOL_ENABLED)
> +			wol->wolopts |= WAKE_MAGIC;
> +	}
>  }
>  
>  static int macb_set_wol(struct net_device *netdev, struct ethtool_wolinfo *wol)
>  {
>  	struct macb *bp = netdev_priv(netdev);
> -	int ret;
>  
> -	ret = phylink_ethtool_set_wol(bp->phylink, wol);
> -	if (!ret)
> -		return 0;
> +	/* Pass the order to phylink layer.
> +	 * Don't test return value as set_wol() is often not supported.
> +	 */
> +	phylink_ethtool_set_wol(bp->phylink, wol);

If this returns an error, does that mean WOL works or does it not?

Note that if set_wol() is not supported, this will return -EOPNOTSUPP.
What about other errors?

If you want to just ignore the case where it's not supported, then
this looks like a sledge hammer to crack a nut.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 10.2Mbps down 587kbps up

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