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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Pavel Machek , Lee Jones , Richard Cochran , Heiner Kallweit , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-leds@vger.kernel.org, Thomas Petazzoni , herve.codina@bootlin.com, maxime.chevallier@bootlin.com, christophercordahi@nanometrics.ca Subject: Re: [PATCH v2 2/6] leds: trigger: Create a new LED netdev trigger for collision Message-ID: References: <20240227093945.21525-1-bastien.curutchet@bootlin.com> <20240227093945.21525-3-bastien.curutchet@bootlin.com> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Russell King (Oracle) On Tue, Feb 27, 2024 at 05:03:14PM +0100, Andrew Lunn wrote: > On Tue, Feb 27, 2024 at 10:39:41AM +0100, Bastien Curutchet wrote: > > Collisions on link does not fit into one of the existing netdev triggers. > > > > Add TRIGGER_NETDEV_COLLISION in the enum led_trigger_netdev_modes. > > Add its definition in Documentation. > > Add its handling in ledtrig-netdev, it can only be supported by hardware > > so no software fallback is implemented. > > How useful is collision? How did you test this? How did you cause > collisions to see if the LED actually worked? > > As far as i can see, this is just a normal 100Base-T PHY. Everybody > uses that point-to-point nowadays. That's largely irrelevant when it comes to collisions. If the link has negotiated half-duplex mode (which we still support) then even on twisted pair, there can be collisions, even though TX and RX are using separate pairs. It's a quirk of 802.3 that this is the case. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!