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Date:   Tue, 4 Oct 2022 12:16:27 +0200
From:   Pavel Machek <pavel@denx.de>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        Junxiao Chang <junxiao.chang@intel.com>,
        Voon Weifeng <weifeng.voon@intel.com>,
        Jimmy JS Chen <jimmyjs.chen@adlinktech.com>,
        "Looi, Hong Aun" <hong.aun.looi@intel.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Sasha Levin <sashal@kernel.org>, Looi@vger.kernel.org
Subject: Re: [PATCH 5.10 46/52] net: stmmac: power up/down serdes in
 stmmac_open/release
Message-ID: <20221004101627.GA30005@duo.ucw.cz>
References: <20221003070718.687440096@linuxfoundation.org>
 <20221003070720.101874721@linuxfoundation.org>
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Hi!

> The issue is related with serdes which impacts clock.  There is
> serdes in ADLink I-Pi SMARC board ethernet controller. Please refer to
> commit b9663b7ca6ff78 ("net: stmmac: Enable SERDES power up/down sequence=
")
> for detial. When issue is reproduced, DMA engine clock is not ready
> because serdes is not powered up.

I don't believe you got the error handling right.

> index 27b7bb64a028..41e71a26b1ad 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -2907,6 +2907,15 @@ static int stmmac_open(struct net_device *dev)
>  		goto init_error;
>  	}
> =20
> +	if (priv->plat->serdes_powerup) {
> +		ret =3D priv->plat->serdes_powerup(dev, priv->plat->bsp_priv);
> +		if (ret < 0) {
> +			netdev_err(priv->dev, "%s: Serdes powerup failed\n",
> +				   __func__);
> +			goto init_error;
> +		}
> +	}

Ok, so serdes is powered up here.

>  	ret =3D stmmac_hw_setup(dev, true);
>  	if (ret < 0) {
>  		netdev_err(priv->dev, "%s: Hw setup failed\n",

But this goes to init_error, and exits w/o powering serdes down. Error
handling needs to be fixed AFAICT.

Best regards,
								Pavel
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