On 21.03.2019 09:38, Andrew Lunn wrote: > On Wed, Mar 20, 2019 at 10:15:10PM +0100, Heiner Kallweit wrote: >> Aquantia PHY's of the AQR107 family support the downshift feature. >> Add support for it as standard PHY tunable so that it can be controlled >> via ethtool. >> The AQCS109 supports a proprietary 2-pair 1Gbps mode. If two such PHY's >> are connected to each other with a 2-pair cable, they may not be able >> to establish a link if both advertise modes >= 1Gbps. Therefore enable >> downshift per default on this model. > > Hi Heiner > > Is there any way to know it has done a downshift? > > Florian said the Intel drivers print a message when they downshift. It > could be interesting to know, especially when a PHY goes from 1G to > 100M. > > Even for a downshift to 1000Base-T2, i'm guessing for most use cases, > this means the cable is partially broken, and it serves as an early > warning it needs replacing. > Good point, after a brief look at the datasheet this should be possible.
> Andrew > . > Heiner
