From: Heiner Kallweit <hkallweit1@gmail.com>
To: Hansen Yang <yanghansen1@163.com>, andrew@lunn.ch
Cc: f.fainelli@gmail.com, davem@davemloft.net,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
496645649@qq.com
Subject: Re: [PATCH] net: phy: marvell: Fix bits clear bug
Date: Sat, 2 Nov 2019 18:00:20 +0100 [thread overview]
Message-ID: <f9972dcf-d586-ca1b-075f-69f4e61721db@gmail.com> (raw)
In-Reply-To: <20191102141508.4416-1-yanghansen1@163.com>
On 02.11.2019 15:15, Hansen Yang wrote:
> The correct way to clear bits before setting some of them is using
> "& = ~BIT_MASK".
> The wrong operation "& = BIT_MASK" will clear other bits.
>
> m88e1116r_config_init() calls marvell_set_polarity() to config
> MDI crossover mode by modifying reg MII_M1011_PHY_SCR, then it
> calls marvell_set_downshift() to config downshift by modifying
> the same reg. According to the bug, marvell_set_downshift()
> clears other bits and set MDI Crossover Mode to Manual MDI
> configuration. If we connect two devices both using this driver
> with a wrong Ethernet cable, they can't automatically adjust
> their crossover mode. Finally they fail to link.
>
Function marvell_set_downshift() doesn't exist any longer.
Note that all new developments should be against net-next.
If you want to submit this as a fix for stable:
- annotate patch as [PATCH net]
- add Fixes tag
- mention that fix applies up to 5.4 only
> Signed-off-by: Hansen Yang <yanghansen1@163.com>
> ---
> drivers/net/phy/marvell.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
> index a7796134e3be..6ab8fe339043 100644
> --- a/drivers/net/phy/marvell.c
> +++ b/drivers/net/phy/marvell.c
> @@ -282,7 +282,7 @@ static int marvell_set_downshift(struct phy_device *phydev, bool enable,
> if (reg < 0)
> return reg;
>
> - reg &= MII_M1011_PHY_SRC_DOWNSHIFT_MASK;
> + reg &= ~MII_M1011_PHY_SRC_DOWNSHIFT_MASK;
> reg |= ((retries - 1) << MII_M1011_PHY_SCR_DOWNSHIFT_SHIFT);
> if (enable)
> reg |= MII_M1011_PHY_SCR_DOWNSHIFT_EN;
>
Heiner
prev parent reply other threads:[~2019-11-02 17:00 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-02 14:15 [PATCH] net: phy: marvell: Fix bits clear bug Hansen Yang
2019-11-02 17:00 ` Heiner Kallweit [this message]
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