Re: Problematic understanding of phy-mode in Rockchip DWMAC driver

From: Yao Zi <me@ziyao.cc>
To: "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc: Heiko Stuebner <heiko@sntech.de>, Andrew Lunn <andrew@lunn.ch>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	netdev@vger.kernel.org, linux-rockchip@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org
Subject: Re: Problematic understanding of phy-mode in Rockchip DWMAC driver
Date: Mon, 16 Feb 2026 04:44:27 +0000	[thread overview]
Message-ID: <aZKgq0-aptu-PnsB@pie> (raw)
In-Reply-To: <aY9xsslT56D9LGLe@shell.armlinux.org.uk>

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.

Thanks for confirming. I understand concerns about regressions and
agree keeping the driver/dts as-is is better.

However, should we mention the difference between "phy-mode" defined
ethernet-controller.yaml and "phy-mode" understood by dwmac-rk
driver in rockchip-dwmac.yaml to avoid confusion in the future?

Regards,
Yao Zi

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