On Wed, Nov 07, 2018 at 09:05:49PM +0100, Heiner Kallweit wrote: > On 07.11.2018 20:48, Andrew Lunn wrote: > > On Wed, Nov 07, 2018 at 08:41:52PM +0100, Heiner Kallweit wrote: > >> This patch series is based on two axioms: > >> > >> - During autoneg a PHY always reports the link being down > > > > Hi Heiner > > > > I think that is a risky assumption to make. > > > I wasn't sure initially too (found no clear rule in 802.3 clause 22) > and therefore asked around. Florian agrees to the assumption, > see here: https://www.spinics.net/lists/netdev/msg519242.html > > If a PHY reports the link as up then every user would assume that > data can be transferred. But that's not the case during aneg. > Therefore reporting the link as up during aneg wouldn't make sense.
Hi Heiner If auto-neg has already been completed once before, i can see a lazy hardware designed not reporting link down, or at least, not until auto-neg actually fails. And what about if link is down for too short a time for us to notice? I've seen some code fail because the kernel went off and did something else for too long, and a state change was missed. > > What happens if this assumption is incorrect? > > > Then we have to flush this patch series down the drain ;) > At least I would have to check in detail which parts need to be > changed. I clearly mention the assumptions so that every > reviewer can check whether he agrees. Thanks for doing that. I want to be happy this is safe, and not going to introduce regressions. Andrew
