Petr Štetiar <ynezz@xxxxxxx> [2022-03-08 13:55:30]:
Hi Greg,
one week has passed and as I didn't received any feedback, I'm providing more
details in a hope to make it more clear, why I think, that this fix is wrong
and should be reverted in LTS kernels 5.10 and 5.15.
> This reverts commit 55dd7e059098ce4bd0a55c251cb78e74604abb57 as it breaks
> network on my A20-olinuxino-lime2 hardware revision "K" which has Micrel
> KSZ9031RNXCC-TR Gigabit PHY. Bastien has probably some previous hardware
> revisions which were based on RTL8211E-VB-CG1 PHY and thus this fix was
> working on his board.
Disclaimer, I don't own A20-olinuxino-lime2 board with earlier HW revisions
G/G1/G2 utilizing RTL8211E PHY.
My understanding is, that up to kernel version 5.9 and specifically commit
bbc4d71d6354 ("net: phy: realtek: fix rtl8211e rx/tx delay config") it was
likely possible to use same DTS for A20-olinuxino-lime2 with KSZ9031 or
RTL8211E PHYs (all HW revisions).
At least I was using my A20-olinuxino-lime2 HW revision K with KSZ9031 PHY
just fine with 4.19 kernel. After upgrade to 5.10 LTS kernel my network
stopped working, reverting stable backport commit a90398438517 ("ARM: dts:
sun7i: A20-olinuxino-lime2: Fix ethernet phy-mode") fixed it.
