Re: Correct method for initializing Pause and Asymmetrical Pause support in phy drivers

On 01/12/2017 04:21 PM, Marc Bertola wrote:

Hello netdev list,

I am currently investigating a problem related to Ethernet
auto-negotiation of Pause and Asymmetrical Pause capabilities.

TL;DR: I am using a Picozed system-on-module with a Xilinx Gigabit
Ethernet MAC and a Marvell PHY. It does not appear to be advertising
support for Pause and Asym Pause, which seems strange to me given that
this is relatively recent hardware. I suspect that may be due to a
problem in the way phydev->supported is initialized in
drivers/net/phy/marvell.c.

I am trying to confirm what the proper method is to initialize
phydev->supported such that it advertises SUPPORTED_Pause and
SUPPORTED_Asym_Pause.  Adding these flags to (phy_driver).features
seems to work, but I would like to confirm with people who are more
knowledgeable than me in this regard.
[...]

This was discussed only recently and iirc consensus was:
* flow control is an ETH property, PHY is only forwarding the info
* => therefore (Asym)Pause flags are to be set by ETH driver, not by PHY

For reference, Timur Tabi cleaned up the PHY drivers around two months ago in [1].


Cheers,
Zefir


[1] https://www.spinics.net/lists/netdev/msg403806.html