netdev - Re: realtek PHY commit bbc4d71d63549 causes regression

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Message-ID: <20201017161435.GA1768480@apalos.home>
Date:   Sat, 17 Oct 2020 19:14:35 +0300
From:   Ilias Apalodimas <ilias.apalodimas@...aro.org>
To:     Ard Biesheuvel <ardb@...nel.org>
Cc:     Andrew Lunn <andrew@...n.ch>,
        "open list:BPF JIT for MIPS (32-BIT AND 64-BIT)" 
        <netdev@...r.kernel.org>, Willy Liu <willy.liu@...ltek.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Sasha Levin <sashal@...nel.org>,
        Florian Fainelli <f.fainelli@...il.com>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Masahisa Kojima <masahisa.kojima@...aro.org>
Subject: Re: realtek PHY commit bbc4d71d63549 causes regression

Hi Ard, 

On Sat, Oct 17, 2020 at 05:18:16PM +0200, Ard Biesheuvel wrote:
> On Sat, 17 Oct 2020 at 17:11, Andrew Lunn <andrew@...n.ch> wrote:
> >
> > On Sat, Oct 17, 2020 at 04:46:23PM +0200, Ard Biesheuvel wrote:
> > > On Sat, 17 Oct 2020 at 16:44, Andrew Lunn <andrew@...n.ch> wrote:
> > > >
> > > > On Sat, Oct 17, 2020 at 04:20:36PM +0200, Ard Biesheuvel wrote:
> > > > > Hello all,
> > > > >
> > > > > I just upgraded my arm64 SynQuacer box to 5.8.16 and lost all network
> > > > > connectivity.
> > > >
> > > > Hi Ard
> > > >
> > > > Please could you point me at the DT files.
> > > >
> > > > > This box has a on-SoC socionext 'netsec' network controller wired to
> > > > > a Realtek 80211e PHY, and this was working without problems until
> > > > > the following commit was merged
> > > >
> > > > It could be this fix has uncovered a bug in the DT file. Before this
> > > > fix, if there is an phy-mode property in DT, it could of been ignored.
> > > > Now the phy-handle property is correctly implemented. So it could be
> > > > the DT has the wrong value, e.g. it has rgmii-rxid when maybe it
> > > > should have rgmii-id.
> > > >
> > >
> > > This is an ACPI system. The phy-mode device property is set to 'rgmii'
> >
> > Hi Ard
> >
> > Please try rgmii-id.
> >
> > Also, do you have the schematic? Can you see if there are any
> > strapping resistors? It could be, there are strapping resistors to put
> > it into rgmii-id. Now that the phy-mode properties is respected, the
> > reset defaults are being over-written to rgmii, which breaks the link.
> > Or the bootloader has already set the PHY mode to rgmii-id.
> >
> > You can also use '' as the phy-mode, which results in
> > PHY_INTERFACE_MODE_NA, which effectively means, don't touch the PHY
> > mode, something else has already set it up. This might actually be the
> > correct way to go for ACPI. In the DT world, we tend to assume the
> > bootloader has done the absolute minimum and Linux should configure
> > everything. The ACPI takes the opposite view, the firmware will do the
> > basic hardware configuration, and Linux should not touch it, or ask
> > ACPI to modify it.
> >
> 
> Indeed, the firmware should have set this up.

Would EDK2 take care of the RGMII Rx/Tx delays even when configured to 
use a DT instead of ACPI?

> This would mean we could > do this in the driver: it currently uses
> 
> priv->phy_interface = device_get_phy_mode(&pdev->dev);
> 
> Can we just assign that to PHY_INTERFACE_MODE_NA instead?

Thanks
/Ilias