linux-kernel - Re: [RFT PATCH 1/2] net: dsa: mv88e6xxx: Add EEE support

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Date:	Mon, 23 Feb 2015 18:34:08 -0800
From:	Florian Fainelli <f.fainelli@...il.com>
To:	Guenter Roeck <linux@...ck-us.net>,
	David Miller <davem@...emloft.net>
CC:	netdev@...r.kernel.org, andrew@...n.ch,
	linux-kernel@...r.kernel.org
Subject: Re: [RFT PATCH 1/2] net: dsa: mv88e6xxx: Add EEE support

On 23/02/15 18:29, Guenter Roeck wrote:
> On 02/23/2015 02:19 PM, David Miller wrote:
>> From: Guenter Roeck <linux@...ck-us.net>
>> Date: Mon, 23 Feb 2015 08:26:09 -0800
>>
>>> +    /* Don't call phy_init_eee for now. It fails if the link is down,
>>> +     * but that should not really be a reason to fail configuration.
>>> +     */
>>
>> I think there is some confusion about phy_init_eee().
>>
>> You invoke it after a link has been established.  Because programming
>> the MDIO registers that turn on EEE can only be done if the link
>> is configured in a certain way.
>>
>> If you look at stmmac, it invokes phy_init_eee() via it's adjust_link
>> callback passed to phy_connect().  This is basically how I would
>> expect it to be used, in that any time a link parameter changes we
>> rerun phy_init_eee() to check the link partner registers, duplex
>> state, etc.
>>
>> SXGBE on the other hand seems to not be using phy_init_eee() properly,
>> it only invokes it once per device open and that makes no sense at all
>> because then you're stuck with the eee state resulting from the link
>> state at open time.
>>
> That explains a lot. I suspect the use in bcm_sf2 and bcmgenet is also
> not as intended.

Yes, it certainly needs fixing.
-- 
Florian
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