Re: [PATCH] pinctrl: sunxi: A523: fix voltage withstand encoding

["Juan Manuel López Carrillo" <juanmanuellopezcarrillo@gmail.com>]

Hi Andre, Chen-Yu,

> So can you please double check this?

Checked on my Orange Pi 4A (T527, GMAC1, Motorcomm YT8531 PHY). You are right:
PJ10 is not needed on this board.

PJ10 function 5 is RGMII1-EPHY-25M, "25 MHz Output for GMAC PHY" in the A523
manual v1.4. The RGMII1 bus itself is the other 15 pins (PJ0-PJ9, PJ11-PJ15),
which mainline already has. My claim came from a stale comment in my tree, from
when I was chasing the dead RX. It is gone now and my rgmii1 group matches
sunxi/for-next. The Tested-by I sent on 22 July was already measured on plain
mainline without PJ10, so what revived RX here was your withstand fix alone.

> Those settings differ from what's in mainline. What are the results with
> those delays?

Measured on the same board, DTB-only changes, TCP for 10 s per direction:

  A  mine (rgmii-rxid, MAC tx 100 / rx 0, PHY rx 1900 ps)
        TX 0.938-0.940   RX 0.929-0.930 Gbit/s
  B  mainline delays (rgmii-id, MAC tx 0 / rx 300, none on the PHY)
        TX 0.941   RX 0.929 Gbit/s
  C  the Ethernet path exactly as mainline has it
     (B, minus motorcomm,auto-sleep-disabled, minus PJ10)
        TX 0.941   RX 0.929 Gbit/s

All three saturate the link, with rx_errs, rx_drop, tx_errs and tx_drop at 0
over roughly 1.6 million packets each. So mine are just other values that
work, and I am dropping them in favour of mainline's.

> ethernet on the A523 has other problems. The performance is really bad
> (even RX), and there are errors or packet drops.

I do not see that on this board, not even with C, which is mainline's Ethernet
DT unmodified. I also checked the YT8531 auto-sleep: the first packet after 5,
10, 20, 30 and 45 s of silence came back in 0.21-0.24 ms, no losses.

The kernel is my own 6.18-based tree, although stmmac and motorcomm.c are
stock, and this is one board with one PHY. Chen-Yu, which board and which MAC
are you seeing it on, and how do you measure it? If it is another board or
GMAC0, I can try to reproduce it here.

Cheers,
Juan