On Wed, Jul 29, 2020 at 06:19:32AM -0700, Richard Cochran wrote: > On Wed, Jul 29, 2020 at 11:58:07AM +0100, Russell King - ARM Linux admin > wrote: > > How do we deal with this situation - from what I can see from the > > ethtool API, we have to make a choice about which to use. How do we > > make that choice? > > Unfortunately the stack does not implement simultaneous MAC + PHY time > stamping. If your board has both, then you make the choice to use the > PHY by selecting NETWORK_PHY_TIMESTAMPING at kernel compile time. > > (Also some MAC drivers do not defer to the PHY properly. Sometimes > you can work around that by de-selecting the MAC's PTP function in the > Kconfig if possible, but otherwise you need to patch the MAC driver.) > > > Do we need a property to indicate whether we wish to use the PHY > > or MAC PTP stamping, or something more elaborate? > > To do this at run time would require quite some work, I expect.
Okay, I'm falling into horrible multicast issues with DSA switches while trying to test. Some of my platforms have IP_MULTICAST=y, others have IP_MULTICAST=n. This causes some to send IGMP messages when binding to the multicast address, others do not. Those that do cause the DSA switch to add a static database entry causing all traffic for that multicast address to be only directed to the port(s) that the machine(s) with IP_MULTICAST=y kernels are connected to, depriving all IP_MULTICAST=n machines from seeing those packets. Maybe, with modern networking technology, it's about time that the kernel configuration help recommended that kernels should be built with IP_MULTICAST=y ? -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
