Messages in this thread | | | Subject | Re: [PATCH net-next v3 10/47] net: phylink: Adjust link settings based on rate adaptation | From | Sean Anderson <> | Date | Sat, 16 Jul 2022 18:37:22 -0400 |
| |
On 7/16/22 4:17 PM, Andrew Lunn wrote: > On Fri, Jul 15, 2022 at 05:59:17PM -0400, Sean Anderson wrote: >> If the phy is configured to use pause-based rate adaptation, ensure that >> the link is full duplex with pause frame reception enabled. Note that these >> settings may be overridden by ethtool. >> >> Signed-off-by: Sean Anderson <sean.anderson@seco.com> >> --- >> >> Changes in v3: >> - New >> >> drivers/net/phy/phylink.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c >> index 7fa21941878e..7f65413aa778 100644 >> --- a/drivers/net/phy/phylink.c >> +++ b/drivers/net/phy/phylink.c >> @@ -1445,6 +1445,10 @@ static void phylink_phy_change(struct phy_device *phydev, bool up) >> pl->phy_state.speed = phy_interface_speed(phydev->interface, >> phydev->speed); >> pl->phy_state.duplex = phydev->duplex; >> + if (phydev->rate_adaptation == RATE_ADAPT_PAUSE) { >> + pl->phy_state.duplex = DUPLEX_FULL; >> + rx_pause = true; >> + } > > I would not do this. If the requirements for rate adaptation are not > fulfilled, you should turn off rate adaptation. > > A MAC which knows rate adaptation is going on can help out, by not > advertising 10Half, 100Half etc. Autoneg will then fail for modes > where rate adaptation does not work.
OK, so maybe it is better to phylink_warn here. Something along the lines of "phy using pause-based rate adaptation, but duplex is %s".
> The MAC should also be declaring what sort of pause it supports, so > disable rate adaptation if it does not have async pause.
That's what we do in the previous patch.
The problem is that rx_pause and tx_pause are resolved based on our advertisement and the link partner's advertisement. However, the link partner may not support pause frames at all. In that case, we will get rx_pause and tx_pause as false. However, we still want to enable rx_pause, because we know that the phy will be emitting pause frames. And of course the user can always force disable pause frames anyway through ethtool.
--Sean
| |