On 25.04.2019 00:41, Andrew Lunn wrote: > On Wed, Apr 24, 2019 at 09:49:30PM +0200, Heiner Kallweit wrote: >> Considering that in polling mode each link drop will be latched, >> settings can't have changed if link was up and is up. > > Hi Heiner > Hi Andrew,
interesting questions. > What about the case of the PHY performing a downshift? > > Could it be up, then finds a pair fails, so performs a downshift. Does > it always report link down and then up to the new speed? Or could it > just shift down? And so we want to read the new speed? > My experience with downshift is that it's part of an extended autoneg process. The link stays down all the time until both link partners have agreed on a downshifted speed. > I suppose it could also perform an upshift? A broken pair comes back > to life, so it returns to the higher speed? > So far I didn't come across an upshift feature. But also then I'd expect some autoneg process with the link being down. More likely seems to be that upshifting requires an explicit autoneg restart. > Andrew > Heiner
