netdev - Re: powering off phys on 'ip link set down'

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4adfeeab-937a-b722-6dd8-84c8a3efb8ac@prevas.dk>
Date:   Thu, 27 Aug 2020 13:00:39 +0200
From:   Rasmus Villemoes <rasmus.villemoes@...vas.dk>
To:     Heiner Kallweit <hkallweit1@...il.com>,
        Network Development <netdev@...r.kernel.org>
Cc:     Lasse Klok Mikkelsen <Lasse.Klok@...vas.se>
Subject: Re: powering off phys on 'ip link set down'

On 27/08/2020 12.29, Heiner Kallweit wrote:
> On 27.08.2020 12:08, Rasmus Villemoes wrote:
>> Hi,
>>
>> We have a requirement that when an interface is taken down
>> administratively, the phy should be powered off. That also works when
>> the interface has link when the 'ip link set down ...' is run. But if
>> there's no cable plugged in, the phy stays powered on (as can be seen
>> both using phytool, and from the fact that a peer gets carrier once a
>> cable is later plugged in).
>>
>> Is this expected behaviour? Driver/device dependent? Can we do anything
>> to force the phy off?
>>
> This may be MAC/PHY-driver dependent. Which driver(s) do we talk about?

It's a Marvell 88e6250 switch (drivers/net/dsa/mv88e6xxx/).

> Also it may depend on whether Runtime PM is active for a PCI network
> device. In addition WoL should be disabled.

The datasheet does mention WoL, but it's either not hooked up in the
driver or at least default disabled, ethtool says

     Supports Wake-on: d
     Wake-on: d

Thanks,
Rasmus