On Sun, Oct 29, 2023 at 06:27:11AM +0200, Cristian Ciocaltea wrote: > The StarFive VisionFive V1 SBC has 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. I'm not so happy this cannot be explained. You are potentially heading into horrible backwards compatibility problems with old DT blobs and new kernels once this is explained and fixed. Andrew