Date:   Mon, 6 Feb 2023 13:22:46 +0200
From:   Vladimir Oltean <olteanv@gmail.com>
To:     Oleksij Rempel <o.rempel@pengutronix.de>
Cc:     Woojung Huh <woojung.huh@microchip.com>,
        UNGLinuxDriver@microchip.com, Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, Wei Fang <wei.fang@nxp.com>,
        Heiner Kallweit <hkallweit1@gmail.com>, kernel@pengutronix.de,
        linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
        Arun.Ramadoss@microchip.com, intel-wired-lan@lists.osuosl.org
Subject: Re: [PATCH net-next v4 02/23] net: phy: add
 genphy_c45_read_eee_abilities() function
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 <20230206104955.GE12366@pengutronix.de>
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On Mon, Feb 06, 2023 at 11:49:55AM +0100, Oleksij Rempel wrote:
> > Why stop at 10GBase-KR? Register 3.20 defines EEE abilities up to 100G
> > (for speeds >10G, there seem to be 2 modes, "deep sleep" or "fast wake",
> > with "deep sleep" being essentially equivalent to the only mode
> > available for <=10G modes).
> 
> Hm,
> 
> If i take only deep sleep, missing modes are:
> 3.20.13 100GBASE-R deep sleep
>        family of Physical Layer devices using 100GBASE-R encoding:
>        100000baseCR4_Full
>        100000baseKR4_Full
>        100000baseCR10_Full (missing)
>        100000baseSR4_Full
>        100000baseSR10_Full (missing)
>        100000baseLR4_ER4_Full
> 
> 3.20.11 25GBASE-R deep sleep
>        family of Physical Layer devices using 25GBASE-R encoding:
>        25000baseCR_Full
>        25000baseER_Full (missing)
>        25000baseKR_Full
>        25000baseLR_Full (missing)
>        25000baseSR_Full
> 
> 3.20.9 40GBASE-R deep sleep
>        family of Physical Layer devices using 40GBASE-R encoding:
>        40000baseKR4_Full
>        40000baseCR4_Full
>        40000baseSR4_Full
>        40000baseLR4_Full
> 
> 3.20.7 40GBASE-T
>        40000baseT_Full (missing)
> 
> I have no experience with modes > 1Gbit. Do all of them correct? What
> should we do with missing modes? Or may be it make sense to implement >
> 10G modes separately?

Given the fact that UAPI needs an extension to cover supported/advertisement
bits > 31, I think it makes sense to add these separately. I had not
realized this when I commented on this patch. I don't think we want the
kernel to advertise EEE for some link modes without user space seeing it.