Problematic understanding of phy-mode in Rockchip DWMAC driver

[Andrew Lunn]

On Fri, Feb 13, 2026 at 06:47:14PM +0000, Russell King (Oracle) wrote:
> On Fri, Feb 13, 2026 at 06:26:44PM +0000, Yao Zi wrote:
> > Hi folks,
> > 
> > I was looking through the RGMII delay setup logic found in
> > rk_gmac_powerup() of dwmac-rk.c, and found its behavior is strange,
> 
> dwmac-rk is very broken and is unfixable thanks to Rockchip not
> understanding the RGMII interface modes used by the kernel.
> 
> It is what it is, we can't change it without causing regressions.
> Please do not try to fix it.

Rockchip have recently started adding support for a new version, and
appear to of listened to what we have been saying. So it could be the
next generation of chips get this correct.

Aspeed are in a similar position, and might also get their next
generation correct.

But as Russell pointed out, we have to be very careful with any
potential changes to this code. Despite it being wrong, boards
work. We cannot fix it and cause regressions.

     Andrew