From: Ido Schimmel <idosch@idosch.org>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Michal Kubecek <mkubecek@suse.cz>,
netdev@vger.kernel.org, davem@davemloft.net, kuba@kernel.org,
f.fainelli@gmail.com, ayal@nvidia.com, danieller@nvidia.com,
amcohen@nvidia.com, mlxsw@nvidia.com,
Ido Schimmel <idosch@nvidia.com>
Subject: Re: [RFC PATCH net] ethtool: Fix incompatibility between netlink and ioctl interfaces
Date: Wed, 30 Sep 2020 17:35:27 +0300 [thread overview]
Message-ID: <20200930143527.GA1824481@shredder> (raw)
In-Reply-To: <20200930141909.GJ3996795@lunn.ch>
On Wed, Sep 30, 2020 at 04:19:09PM +0200, Andrew Lunn wrote:
> > > I don't think so. Doing:
> > >
> > > # ethtool -s eth0 autoneg
> > >
> > > Is a pretty established behavior to enable all the supported advertise
> > > bits.
>
> I would disagree. phylib will return -EINVAL for this.
This has nothing to do with the kernel / phylib. With the ioctl
interface when you do:
# ethtool -s eth0 autoneg on
The ethtool user space utility will enable all the supported link modes:
https://git.kernel.org/pub/scm/network/ethtool/ethtool.git/tree/ethtool.c#n3170
For the netlink interface this is done by the kernel:
https://github.com/torvalds/linux/blob/master/net/ethtool/linkmodes.c#L2
But only if speed or duplex were specified:
https://github.com/torvalds/linux/blob/master/net/ethtool/linkmodes.c#L383
Which is a problem.
>
> int phy_ethtool_ksettings_set(struct phy_device *phydev,
> const struct ethtool_link_ksettings *cmd)
> {
> __ETHTOOL_DECLARE_LINK_MODE_MASK(advertising);
> u8 autoneg = cmd->base.autoneg;
> u8 duplex = cmd->base.duplex;
> u32 speed = cmd->base.speed;
>
> ...
> linkmode_copy(advertising, cmd->link_modes.advertising);
>
> ...
>
> if (autoneg == AUTONEG_ENABLE && linkmode_empty(advertising))
> return -EINVAL;
>
> You have to pass a list of modes you want it to advertise. If you are
> using phylink and not a copper PHY, and autoneg, that means you are
> using in-band signalling. The same is imposed:
>
> /* If autonegotiation is enabled, we must have an advertisement */
> if (config.an_enabled && phylink_is_empty_linkmode(config.advertising))
> return -EINVAL;
>
> We have consistent behaviour whenever Linux is controlling the PHY
> because the core is imposing that behaviour. It would be nice if
> drivers ignoring the PHY core where consistent with this.
You will get an error from mlxsw as well (see example in the change
log).
>
> Andrew
next prev parent reply other threads:[~2020-09-30 14:35 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-29 16:02 [RFC PATCH net] ethtool: Fix incompatibility between netlink and ioctl interfaces Ido Schimmel
2020-09-29 16:44 ` Michal Kubecek
2020-09-30 7:25 ` Ido Schimmel
2020-09-30 8:59 ` Michal Kubecek
2020-09-30 14:19 ` Andrew Lunn
2020-09-30 14:35 ` Ido Schimmel [this message]
2020-09-30 14:43 ` Ido Schimmel
2020-09-30 20:06 ` Ido Schimmel
2020-09-30 20:45 ` Michal Kubecek
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