linux-kernel - Re: [PATCH net-next v2 06/10] net: phy: print an info if a broken C45 bus is found

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Message-ID: <af166ce6-b9b2-44e0-9f45-2b2aa001fd6b@lunn.ch>
Date:   Fri, 23 Jun 2023 19:42:08 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Michael Walle <mwalle@...nel.org>
Cc:     Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Yisen Zhuang <yisen.zhuang@...wei.com>,
        Salil Mehta <salil.mehta@...wei.com>,
        Florian Fainelli <florian.fainelli@...adcom.com>,
        Broadcom internal kernel review list 
        <bcm-kernel-feedback-list@...adcom.com>,
        Marek Behún <kabel@...nel.org>,
        Xu Liang <lxu@...linear.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next v2 06/10] net: phy: print an info if a broken
 C45 bus is found

On Fri, Jun 23, 2023 at 12:29:15PM +0200, Michael Walle wrote:
> If there is an PHY which gets confused by C45 transactions on the MDIO
> bus, print an info together with the PHY identifier of the offending
> one.
> 
> Signed-off-by: Michael Walle <mwalle@...nel.org>
> 
> ---
> I wasn't sure if this should be phydev_dbg() or phydev_info(). I mainly
> see this as an info to a user why some PHYs might not be probed (or
> c45-over-c22 is used later).

The information is useful to the DT writer, not the 'user'. I would
assume the DT writer has a bit more kernel knowledge and can debug
prints on. So i would suggest phydev_dbg().

> @@ -617,10 +617,10 @@ static int mdiobus_scan_bus_c45(struct mii_bus *bus)
>   */
>  void mdiobus_scan_for_broken_c45_access(struct mii_bus *bus)
>  {
> +	struct phy_device *phydev;
>  	int i;
>  
>  	for (i = 0; i < PHY_MAX_ADDR; i++) {
> -		struct phy_device *phydev;
>  		u32 oui;

It is not clear why you changed the scope of phydev. I guess another
version used phydev_info(), where as now you have dev_info()?

	Andrew

>  
>  		phydev = mdiobus_get_phy(bus, i);
> @@ -633,6 +633,11 @@ void mdiobus_scan_for_broken_c45_access(struct mii_bus *bus)
>  			break;
>  		}
>  	}
> +
> +	if (bus->prevent_c45_access)
> +		dev_info(&bus->dev,
> +			 "Detected broken PHY (ID %08lx). Disabling C45 bus transactions.\n",
> +			 (unsigned long)phydev->phy_id);
>  }
>  
>  /**
> 
> -- 
> 2.39.2
>