linux-kernel - Re: [RFC] net: dsa: slave: Advertise correct EEE capabilities at slave PHY setup

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: <20230530154039.4552e08a@wsk>
Date:   Tue, 30 May 2023 15:40:39 +0200
From:   Lukasz Majewski <lukma@...x.de>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     Russell King <linux@...linux.org.uk>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Vladimir Oltean <olteanv@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC] net: dsa: slave: Advertise correct EEE capabilities at
 slave PHY setup

Hi Andrew,

> On Tue, May 30, 2023 at 02:26:21PM +0200, Lukasz Majewski wrote:
> > One can disable in device tree advertising of EEE capabilities of
> > PHY when 'eee-broken-100tx' property is present in DTS.
> > 
> > With DSA switch it also may happen that one would need to disable
> > EEE due to some network issues.  
> 
> Is EEE actually broken in the MAC/PHY combination?
> 

Problem is that when I connect on this project some non-manageable
switches (which by default have EEE enabled), then I observe very rare
and sporadic link loss and reconnection.

Disabling EEE solves the problem.

> You should not be using this DT option for configuration. It is there
> because there is some hardware which is truly broken, and needs EEE
> turned off.

Yes, I do think that the above sentence sums up my use case.

> 
> If EEE does work, but you need to turn it off because of latency etc,
> then please use ethtool.
> 

Yes, correct - it is possible to disable the EEE with 

ethtool --set-eee lan2 eee off

However, as I've stated in the mail, I cannot re-enable EEE once
disabled with:

ethtool --set-eee lan2 eee on

ethtool --show-eee lan2
EEE Settings for lan2:
        EEE status: not supported


As the capability register shows value of 0.

>      Andrew,




Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Erika Unter
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@...x.de

Content of type "application/pgp-signature" skipped