linux-kernel - Re: Question: pause mode disabled for marvell 88e151x phy

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Message-ID: <20190123224144.imzntelxqtf3xcuj@e5254000004ec.dyn.armlinux.org.uk>
Date:   Wed, 23 Jan 2019 22:41:44 +0000
From:   Russell King - ARM Linux admin <linux@...linux.org.uk>
To:     Yunsheng Lin <linyunsheng@...wei.com>
Cc:     Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Weiwei Deng <dengweiwei@...wei.com>,
        "Yisen.Zhuang@...wei.com" <Yisen.Zhuang@...wei.com>,
        "huangdaode@...ilicon.com" <huangdaode@...ilicon.com>,
        "lipeng321@...wei.com" <lipeng321@...wei.com>,
        "salil.mehta@...wei.com" <salil.mehta@...wei.com>,
        lijianhua 00216010 <lijianhua@...wei.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Question: pause mode disabled for marvell 88e151x phy

On Sat, Jan 05, 2019 at 11:28:19AM +0800, Yunsheng Lin wrote:
> On 2018/12/17 22:36, Russell King - ARM Linux wrote:
> > I'll try to do further diagnosis over Christmas in case I've missed
> > something, but I suspect it may be one of those "weird behaviour" issues
> > where the safest action is to disable pause mode as per my commit -
> > which is far saner than having mismatched pause status on either end
> > of a link.  However, given that Marvell specs are all NDA-only, it's
> > very difficult to investigate beyond "this is the observed behaviour".
> 
> Hi,
> 
> Is there any update on the further diagnosis?

Hi,

I've finally been able to do some further diagnosis (with a 'scope).
It would appear that the network adapter had PHY polling enabled,
which meant that it overwrote the PHYs advertisement register
during negotiation.  I thought I'd checked that scenario, but alas
clearing the PHY poll enable bit on its own doesn't stop it polling!

I'll send a revert for the commit shortly.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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