On 1/31/2020 5:30 PM, Dan Murphy wrote:

Heiner

On 1/31/20 2:56 PM, Heiner Kallweit wrote:

quoted

On 31.01.2020 16:11, Dan Murphy wrote:

quoted

Set the speed optimization bit on the DP83867 PHY.
This feature can also be strapped on the 64 pin PHY devices
but the 48 pin devices do not have the strap pin available to enable
this feature in the hardware.  PHY team suggests to have this bit set.

It's ok to enable downshift by default, however it would be good to
make it configurable. Best implement the downshift tunable, you can
use the Marvell PHY driver as reference.
Can the number of attempts until downshifts happens be configured?

Yes we can tune the number of attempts it makes to negotiate 1000Mbps
before enabling the speed optimization.  But why would we need to
configure the number of attempts currently it is defaulted to 4.  Is
there a use case for this level of configurability?

Some customers may prefer a fast(er) link re-negotiation once they know
the cabling is faulty or sub-optimal. The default is usually fine, and
if you want to support the downshift ethtool tunable when net-next opens
back up, that would be a welcome addition.
-- 
Florian