Re: [Intel-wired-lan] [PATCH net-next v2] drivers/net/ethernet: check return value of e1e_rphy()

From: "Neftin, Sasha" <sasha.neftin@intel.com>
To: Li Zhong <floridsleeves@gmail.com>, <netdev@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>,
	<intel-wired-lan@lists.osuosl.org>
Cc: "Fuxbrumer, Devora" <devora.fuxbrumer@intel.com>,
	edumazet@google.com, "Ruinskiy, Dima" <dima.ruinskiy@intel.com>,
	kuba@kernel.org, pabeni@redhat.com, davem@davemloft.net
Subject: Re: [Intel-wired-lan] [PATCH net-next v2] drivers/net/ethernet: check return value of e1e_rphy()
Date: Mon, 29 Aug 2022 21:03:21 +0300	[thread overview]
Message-ID: <3226a822-b8be-b712-737a-f8cc523ebed1@intel.com> (raw)
In-Reply-To: <20220826065627.1615965-1-floridsleeves@gmail.com>

On 8/26/2022 09:56, Li Zhong wrote:
> e1e_rphy() could return error value, which needs to be checked and
> reported for debugging and diagnose.
> 
> Signed-off-by: Li Zhong <floridsleeves@gmail.com>
> ---
>   drivers/net/ethernet/intel/e1000e/phy.c | 20 +++++++++++++++++---
>   1 file changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/e1000e/phy.c b/drivers/net/ethernet/intel/e1000e/phy.c
> index fd07c3679bb1..060b263348ce 100644
> --- a/drivers/net/ethernet/intel/e1000e/phy.c
> +++ b/drivers/net/ethernet/intel/e1000e/phy.c
> @@ -2697,9 +2697,14 @@ static s32 e1000_access_phy_wakeup_reg_bm(struct e1000_hw *hw, u32 offset,
>   void e1000_power_up_phy_copper(struct e1000_hw *hw)
>   {
>   	u16 mii_reg = 0;
> +	int ret;
>   
>   	/* The PHY will retain its settings across a power down/up cycle */
> -	e1e_rphy(hw, MII_BMCR, &mii_reg);
> +	ret = e1e_rphy(hw, MII_BMCR, &mii_reg);
> +	if (ret) {
> +		e_dbg("Error reading PHY register\n");
> +		return;
> +	}
>   	mii_reg &= ~BMCR_PDOWN;
>   	e1e_wphy(hw, MII_BMCR, mii_reg);
>   }
> @@ -2715,9 +2720,14 @@ void e1000_power_up_phy_copper(struct e1000_hw *hw)
>   void e1000_power_down_phy_copper(struct e1000_hw *hw)
>   {
>   	u16 mii_reg = 0;
> +	int ret;
>   
>   	/* The PHY will retain its settings across a power down/up cycle */
> -	e1e_rphy(hw, MII_BMCR, &mii_reg);
> +	ret = e1e_rphy(hw, MII_BMCR, &mii_reg);
> +	if (ret) {
> +		e_dbg("Error reading PHY register\n");
> +		return;
> +	}
>   	mii_reg |= BMCR_PDOWN;
>   	e1e_wphy(hw, MII_BMCR, mii_reg);
>   	usleep_range(1000, 2000);
> @@ -3037,7 +3047,11 @@ s32 e1000_link_stall_workaround_hv(struct e1000_hw *hw)
>   		return 0;
>   
>   	/* Do not apply workaround if in PHY loopback bit 14 set */
> -	e1e_rphy(hw, MII_BMCR, &data);
> +	ret_val = e1e_rphy(hw, MII_BMCR, &data);
> +	if (ret_val) {
> +		e_dbg("Error reading PHY register\n");
> +		return ret_val;
> +	}
>   	if (data & BMCR_LOOPBACK)
>   		return 0;
>   
Generally, I am good with this patch. One question - it is old HW, any 
idea how to check it? (82577/82578 GbE LOM - from 2008)
Li, how did you check it manually?
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