netdev - Re: [PATCH net-next 1/2] ethtool: add PHY Fast Link Down support

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: <96fe4e87-f51a-e3ce-ae72-a726b3db53be@gmail.com>
Date:   Tue, 26 Mar 2019 19:24:57 +0100
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Andrew Lunn <andrew@...n.ch>, Michal Kubecek <mkubecek@...e.cz>
Cc:     Florian Fainelli <f.fainelli@...il.com>,
        David Miller <davem@...emloft.net>,
        "John W. Linville" <linville@...driver.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next 1/2] ethtool: add PHY Fast Link Down support

On 26.03.2019 09:24, Andrew Lunn wrote:
>>> +#define ETHTOOL_PHY_FAST_LINK_DOWN_ON	0
>>> +#define ETHTOOL_PHY_FAST_LINK_DOWN_OFF	0xff
>>> +
>>>  enum phy_tunable_id {
>>>  	ETHTOOL_PHY_ID_UNSPEC,
>>>  	ETHTOOL_PHY_DOWNSHIFT,
>>> +	ETHTOOL_PHY_FAST_LINK_DOWN,
>>>  	/*
>>>  	 * Add your fresh new phy tunable attribute above and remember to update
>>>  	 * phy_tunable_strings[] in net/core/ethtool.c
>>
>> It would be nice to have a short summary around here explaining how is
>> the value interpreted. While it's obvious from the second patch, one
>> shouldn't have to go into driver specific implementation to find out.
>>
>> I also wonder if the range 0-254 ms is sufficient. Would it be possible
>> that there is some other hardware which would support e.g. 300 ms?
> 
> The default, as defined by the 802.3 standard, is i think 750ms.
> 
Clause 40. From what I've found this applies to 1000BaseT only.

> The Marvel PHY also supports 50ms, 20ms and 0ms, if i remember
> correctly.
> 
0, 10, 20, 40ms (at least for 88E1540 and 88E6390)

> One problem we have here is discovery. How does the user find out the
> values the driver supports. For a netlink socket API, extended errors
> could be used to pass back a string indicating the supported
> values. For the old ethtool, i think all we have is -EINVAL, which is
> not very helpful.
> 
> 	Andrew
> .
> 
Heiner