PHY down?

PHY down?

[Joakim Tjernlund]

I must be missing something obvious but I cannot find how
to bring eth0's PHY down (link down) from user space.
Tried various settings with ethtool and ifconfig eth0 down but it didn't help.

 Jocke

Re: PHY down?

[Ben Hutchings]

On Tue, 2011-08-02 at 11:24 +0200, Joakim Tjernlund wrote:
> I must be missing something obvious but I cannot find how
> to bring eth0's PHY down (link down) from user space.
> Tried various settings with ethtool and ifconfig eth0 down but it didn't help.

If you configure an interface down, and if the interface is not used for
remote management, then some drivers will turn the PHY off.  But there
is no general way to control this explicitly.

Ben.

-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

Re: PHY down?

[Joakim Tjernlund]

Ben Hutchings <bhutchings@solarflare.com> wrote on 2011/08/02 13:01:08:
>
> On Tue, 2011-08-02 at 11:24 +0200, Joakim Tjernlund wrote:
> > I must be missing something obvious but I cannot find how
> > to bring eth0's PHY down (link down) from user space.
> > Tried various settings with ethtool and ifconfig eth0 down but it didn't help.
>
> If you configure an interface down, and if the interface is not used for
> remote management, then some drivers will turn the PHY off.  But there
> is no general way to control this explicitly.

OK, when to stop the PHY doesn't seem standardized. Seem logical to me
to also turn off the PHY when interface is configured down. Perhaps this could
be agreed upon?
What does remote management mean? How do I identify if the I/F is used for remote management?

 Jocke

>
> Ben.

Re: PHY down?

[Ben Hutchings]

On Tue, 2011-08-02 at 14:24 +0200, Joakim Tjernlund wrote:
> Ben Hutchings <bhutchings@solarflare.com> wrote on 2011/08/02 13:01:08:
> >
> > On Tue, 2011-08-02 at 11:24 +0200, Joakim Tjernlund wrote:
> > > I must be missing something obvious but I cannot find how
> > > to bring eth0's PHY down (link down) from user space.
> > > Tried various settings with ethtool and ifconfig eth0 down but it didn't help.
> >
> > If you configure an interface down, and if the interface is not used for
> > remote management, then some drivers will turn the PHY off.  But there
> > is no general way to control this explicitly.
> 
> OK, when to stop the PHY doesn't seem standardized. Seem logical to me
> to also turn off the PHY when interface is configured down. Perhaps this could
> be agreed upon?
> What does remote management mean? How do I identify if the I/F is used for remote management?

Most server motherboards have some sort of lights-out management (LOM)
faclity.  This is usually accessible when the server is switched on, as
well.  It may share a network port or ports with the host OS.

There is no general way to tell whether this is supported or enabled on
an interface, but it should be described in motherboard documentation or
the firmware configuration program (BIOS setup).

Ben.

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

Re: PHY down?

[Edgar E. Iglesias]

On Tue, Aug 02, 2011 at 02:24:04PM +0200, Joakim Tjernlund wrote:
> Ben Hutchings <bhutchings@solarflare.com> wrote on 2011/08/02 13:01:08:
> >
> > On Tue, 2011-08-02 at 11:24 +0200, Joakim Tjernlund wrote:
> > > I must be missing something obvious but I cannot find how
> > > to bring eth0's PHY down (link down) from user space.
> > > Tried various settings with ethtool and ifconfig eth0 down but it didn't help.
> >
> > If you configure an interface down, and if the interface is not used for
> > remote management, then some drivers will turn the PHY off.  But there
> > is no general way to control this explicitly.
> 
> OK, when to stop the PHY doesn't seem standardized. Seem logical to me
> to also turn off the PHY when interface is configured down. Perhaps this could
> be agreed upon?
> What does remote management mean? How do I identify if the I/F is used for remote management?
> 
>  Jocke

I'd rather see an explicit way of turning off the PHY. Downing the interface might be
useful without killing the PHY. I've seen PoE switches that kill you when you bring
the link down or reset the PHY after once beeing up, Down/up of interface might become
impossible in some environments if we would standardize on PHY off for interface down.

Maybe an explicit ethtool option?

Cheers