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Date:   Thu, 22 Jun 2023 13:54:25 -0500
From:   Andrew Halaney <ahalaney@redhat.com>
To:     Bartosz Golaszewski <brgl@bgdev.pl>
Cc:     Giuseppe Cavallaro <peppe.cavallaro@st.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Jose Abreu <joabreu@synopsys.com>,
        "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Junxiao Chang <junxiao.chang@intel.com>,
        netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Subject: Re: [PATCH net] net: stmmac: fix double serdes powerdown
Message-ID: <20230622185425.vfewm2qgxqpndfyf@halaney-x13s>
References: <20230621135537.376649-1-brgl@bgdev.pl>
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On Wed, Jun 21, 2023 at 03:55:37PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> Commit 49725ffc15fc ("net: stmmac: power up/down serdes in
> stmmac_open/release") correctly added a call to the serdes_powerdown()
> callback to stmmac_release() but did not remove the one from
> stmmac_remove() which leads to a doubled call to serdes_powerdown().
> 
> This can lead to all kinds of problems: in the case of the qcom ethqos
> driver, it caused an unbalanced regulator disable splat.
> 
> Fixes: 49725ffc15fc ("net: stmmac: power up/down serdes in stmmac_open/release")
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Reviewed-by: Andrew Halaney <ahalaney@redhat.com>
Tested-by: Andrew Halaney <ahalaney@redhat.com>

> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 10e8a5606ba6..4727f7be4f86 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -7461,12 +7461,6 @@ void stmmac_dvr_remove(struct device *dev)
>  	netif_carrier_off(ndev);
>  	unregister_netdev(ndev);
>  
> -	/* Serdes power down needs to happen after VLAN filter
> -	 * is deleted that is triggered by unregister_netdev().
> -	 */
> -	if (priv->plat->serdes_powerdown)
> -		priv->plat->serdes_powerdown(ndev, priv->plat->bsp_priv);
> -
>  #ifdef CONFIG_DEBUG_FS
>  	stmmac_exit_fs(ndev);
>  #endif
> -- 
> 2.39.2
>