Date:   Thu, 25 Nov 2021 15:47:10 +0100
From:   Andrew Lunn <andrew@lunn.ch>
To:     Dylan Hung <dylan_hung@aspeedtech.com>
Cc:     linux-kernel@vger.kernel.org, linux-aspeed@lists.ozlabs.org,
        linux-arm-kernel@lists.infradead.org, netdev@vger.kernel.org,
        andrew@aj.id.au, joel@jms.id.au, kuba@kernel.org,
        davem@davemloft.net, linux@armlinux.org.uk, hkallweit1@gmail.com,
        BMC-SW@aspeedtech.com, stable@vger.kernel.org
Subject: Re: [PATCH v2] mdio: aspeed: Fix "Link is Down" issue
Message-ID: <YZ+h7qXTLvRRXpj0@lunn.ch>
References: <20211125024432.15809-1-dylan_hung@aspeedtech.com>
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On Thu, Nov 25, 2021 at 10:44:32AM +0800, Dylan Hung wrote:
> The issue happened randomly in runtime.  The message "Link is Down" is
> popped but soon it recovered to "Link is Up".
> 
> The "Link is Down" results from the incorrect read data for reading the
> PHY register via MDIO bus.  The correct sequence for reading the data
> shall be:
> 1. fire the command
> 2. wait for command done (this step was missing)
> 3. wait for data idle
> 4. read data from data register
> 
> Fixes: f160e99462c6 ("net: phy: Add mdio-aspeed")
> Cc: stable@vger.kernel.org
> Reviewed-by: Joel Stanley <joel@jms.id.au>
> Signed-off-by: Dylan Hung <dylan_hung@aspeedtech.com>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew