Hi Geert,

On Fri, Jul 20, 2018 at 5:09 AM, Geert Uytterhoeven
<[email protected]> wrote:
> On Thu, Jul 19, 2018 at 7:56 PM Sergei Shtylyov
> <[email protected]> wrote:
>> On 07/19/2018 08:42 PM, Geert Uytterhoeven wrote:
>> >>>> From: Magnus Damm <[email protected]>
>> >>>> According to the data sheet the Ethernet-AVB hardware in R-Car Gen3
>> >>>> and R-Car Gen2 SoCs do not support half duplex operation. So update
>> >>>> the driver to mark 100Mbit HDX as unsupported.
>> >>>
>> >>>    What about 1000Mbit HDX?
>> >>
>> >> For Twister Pair I believe 10 and 100 Mbps come in HDX and FDX flavors
>> >> while 1 Gbps is HDX-only.
>> >
>> >  1 Gbps is _F_DX-only?
>>
>>    No, only higher speeds are FDX only.
>>
>> >> https://en.wikipedia.org/wiki/Ethernet_over_twisted_pair
>
> That wiki page says "However, half-duplex operation for gigabit speed isn't
> supported by any existing hardware.".

Exactly. Also the PHY data sheet might have some additional
information about bitmaps for advertised and supported modes.

> Running ethtool on a few systems shows that some of them don't support it, 
> while
> others do.

Amen. Nice to see that at least someone else is using ethtool to test
link configuration. =/

Thanks,

/ magnus

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