Re: [PATCH net-next 5/7] net: phy: marvell10g: Force reading of 2.5/5G PMA extended abilities

On Fri, Jan 18, 2019 at 04:23:50PM +0100, Maxime Chevallier wrote:

As per 802.3bz, if bit 14 of (1.11) "PMA Extended Abilities" indicates
whether or not we should read register (1.21) "2.52/5G PMA Extended
Abilities", which contains information on the support of 2.5GBASET and
5GBASET.

After testing on several variants of PHYS of this family, it appears
that bit 14 in (1.11) isn't always set when it should be.

PHYs 88X3310 (on MacchiatoBin) and 88E2010 do support 2.5G and 5GBASET,
but don't have 1.11.14 set. Their register 1.21 is filled with the
correct values, indicating 2.5G and 5G support.

PHYs 88X2110 do have their 1.11.14 bit set, as it should.

Hi Maxime

Is there anything about this in any Errata?

We potentially have an issue if Marvell have any PHYs in this family
which don't support 2.5G/5G. Maybe this workaround needs to check the
IDs and only enable it on device we know are broken.

    Andrew

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