Re: [PATCH RFC net-next 5/6] net: dsa: always use phylink for CPU and DSA ports

From: "Marek Behún" <kabel@kernel.org>
To: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Cc: Andrew Lunn <andrew@lunn.ch>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	"Alvin __ipraga" <alsi@bang-olufsen.dk>,
	Claudiu Manoil <claudiu.manoil@nxp.com>,
	"David S. Miller" <davem@davemloft.net>,
	DENG Qingfang <dqfext@gmail.com>,
	Eric Dumazet <edumazet@google.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	George McCollister <george.mccollister@gmail.com>,
	Hauke Mehrtens <hauke@hauke-m.de>,
	Jakub Kicinski <kuba@kernel.org>,
	Kurt Kanzenbach <kurt@linutronix.de>,
	Landen Chao <Landen.Chao@mediatek.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org,
	Matthias Brugger <matthias.bgg@gmail.com>,
	netdev@vger.kernel.org, Paolo Abeni <pabeni@redhat.com>,
	Sean Wang <sean.wang@mediatek.com>,
	UNGLinuxDriver@microchip.com,
	Vivien Didelot <vivien.didelot@gmail.com>,
	Vladimir Oltean <olteanv@gmail.com>,
	Woojung Huh <woojung.huh@microchip.com>
Subject: Re: [PATCH RFC net-next 5/6] net: dsa: always use phylink for CPU and DSA ports
Date: Fri, 1 Jul 2022 21:34:35 +0200	[thread overview]
Message-ID: <20220701213435.53ecdd70@thinkpad> (raw)
In-Reply-To: <E1o6XAV-004pW2-Ct@rmk-PC.armlinux.org.uk>

On Wed, 29 Jun 2022 13:51:43 +0100
"Russell King (Oracle)" <rmk+kernel@armlinux.org.uk> wrote:

> Currently, we only use phylink for CPU and DSA ports if there is a
> fixed-link specification, or a PHY specified. The reason for this
> behaviour is that when neither is specified, there was no way for
> phylink to know the link parameters.
> 
> Now that we have phylink_set_max_link_speed() (which has become
> possible through the addition of mac_capabilities) we now have the
> ability to know the maximum link speed for a specific link, and can
> now use phylink for this case as well.
> 
> However, we need DSA drivers to report the interface mode being used
> on these ports so that we can select a maximum speed appropriate for
> the interface mode that hardware may have configured for the port.
> 
> This is especially important with the conversion of DSA drivers to
> phylink_pcs, as the PCS code only gets called if we are using
> phylink for the port.
> 
> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

Reviewed-by: Marek Behún <kabel@kernel.org>

So this is the one that may break other drivers?

Marek