On Fri, Dec 15, 2023 at 10:40:45PM +0200, Cristian Ciocaltea wrote:
The StarFive VisionFive V1 SBC uses a Motorcomm YT8521 PHY supporting
RGMII-ID, but requires manual adjustment of the RX internal delay to
work properly.
The default RX delay provided by the driver is 1.95 ns, which proves to
be too high. Applying a 50% reduction seems to mitigate the issue.
Also note this adjustment is not necessary on BeagleV Starlight SBC,
which uses a Microchip PHY. Hence, there is no indication of a
miss-behaviour on the GMAC side, but most likely the issue stems from
the Motorcomm PHY.
I suggest you make a similar comment in the .dts file, just to explain
the odd setting.
Andrew