Re: [PATCH net-next v11 02/15] phylib: Add support for PHYs with broken forced mode

[Nicolai Buchwitz <nb@tipi-net.de>]

On 14.9.2026 14:46, Birger Koblitz wrote:
> Add support for PHYs which only supported auto-negotiated
> speed modes. This prevents a kernel warning and stack-trace within the
> phy_state_machine when PHYs return -EOPNOTSUPP from config_aneg()
> because they do not support forced modes.
> 
> Signed-off-by: Birger Koblitz <mail@birger-koblitz.de>
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
> ---
>  drivers/net/phy/phy.c | 4 ++++
>  include/linux/phy.h   | 1 +
>  2 files changed, 5 insertions(+)
> 
> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
> index 
> fce9bc7be3304b408c9f3ec9b5b95c76d3680a88..b83f938fe7c3bd619ae453434fd9582c0a055a57 
> 100644
> --- a/drivers/net/phy/phy.c
> +++ b/drivers/net/phy/phy.c
> @@ -1190,6 +1190,10 @@ int phy_ethtool_ksettings_set(struct phy_device 
> *phydev,
>  	      duplex != DUPLEX_FULL)))
>  		return -EINVAL;
> 
> +	if (autoneg == AUTONEG_DISABLE &&
> +	    (phydev->drv->flags & PHY_BROKEN_FORCED))
> +		return -EOPNOTSUPP;
> +
>  	mutex_lock(&phydev->lock);
>  	phydev->autoneg = autoneg;
> 
> diff --git a/include/linux/phy.h b/include/linux/phy.h
> index 
> 5f8d65868e0ff558c163421cfea5a6f3bd73a53e..d5f8e527ce8dfefd40a8b34e7c2f9adbcd6c87c1 
> 100644
> --- a/include/linux/phy.h
> +++ b/include/linux/phy.h
> @@ -64,6 +64,7 @@ extern const int phy_basic_ports_array[3];
>  #define PHY_RST_AFTER_CLK_EN	0x00000002
>  #define PHY_POLL_CABLE_TEST	0x00000004
>  #define PHY_ALWAYS_CALL_SUSPEND	0x00000008
> +#define PHY_BROKEN_FORCED	0x00000010
>  #define MDIO_DEVICE_IS_PHY	0x80000000
> 
>  /**


Reviewed-by: Nicolai Buchwitz <nb@tipi-net.de>

Thanks,
Nicolai