Re: [PATCH 07/12] dt-bindings: net: Add StarFive JH7100 SoC

[Cristian Ciocaltea]

On 2/16/23 19:54, Andrew Lunn wrote:
> > I gave "rgmii-id" a try and it's not usable, I get too many errors. So
> > "rgmii" should be the right choice here.
>
> I would actually say it shows we don't understand what is going on
> with delays. "rgmii" is not every often the correct value. The fact it
> works suggests the MAC is adding delays.
>
> What value are you using for starfive,gtxclk-dlychain ? 

This is set to '4' in patch 12/12.

> Try 0 and then "rgmii-id"

I made some more tests and it seems the only stable configuration is 
"rgmii" with "starfive,gtxclk-dlychain" set to 4:

phy-mode | dlychain | status
---------+----------+--------------------------------------------
rgmii    |        4 | OK (no issues observed)
rgmii-id |        4 | BROKEN (errors reported [1])
rgmii    |        0 | UNRELIABLE (no errors, but frequent stalls)
rgmii-id |        0 | BROKEN (errors reported)

[1] Reported errors in case of BROKEN status:
$ grep '' /sys/class/net/eth0/statistics/* | grep -v ':0$'

/sys/class/net/eth0/statistics/rx_crc_errors:6
/sys/class/net/eth0/statistics/rx_errors:6
/sys/class/net/eth0/statistics/tx_bytes:10836
/sys/class/net/eth0/statistics/tx_packets:46

> 	Andrew