From: David Miller <davem@davemloft.net>
To: sebastian.hesselbarth@gmail.com
Cc: netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC v1 0/7] net: phy: Ethernet PHY powerdown optimization
Date: Wed, 20 Nov 2013 15:36:42 -0500 (EST) [thread overview]
Message-ID: <20131120.153642.2045230991917379052.davem@davemloft.net> (raw)
In-Reply-To: <1384978913-8052-1-git-send-email-sebastian.hesselbarth@gmail.com>
From: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Date: Wed, 20 Nov 2013 21:21:46 +0100
> Ethernet PHYs consume a significant amount of power when link is detected.
> Especially, for embedded systems it can be easily 20-40% of total system
> power. Now, currently most likely all ethernet drivers leave PHYs powered
> on, even if the device is taken down. Also, some stupid boot loaders power
> on all PHYs available.
>
> This RFC deals with saving power consumed by ethernet PHYs, that have no
> corresponding ethernet device driver or are attached to ethernet devices
> which are taken down by user request, i.e. ifconfig ethN down. Ports with
> no link, i.e. cable removed, are already quite good at power saving due to
> PHY internal link detection.
The idea is sound and the goal is of course valuable, but it brings up
a chronically reoccurring issue as of late.
You cannot reset the PHY or take it down without somehow retaining the
settings the PHY had when you bring it back up.
If I ifdown/ifup a device, my ethtool link configuration better be
retained.
This means the PHY layer must have a way to reprogram the device when
it is brought back up, with whatever settings the software state
things are there.
next prev parent reply other threads:[~2013-11-20 20:36 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-20 20:21 [PATCH RFC v1 0/7] net: phy: Ethernet PHY powerdown optimization Sebastian Hesselbarth
2013-11-20 20:21 ` [PATCH RFC v1 1/7] net: phy: marvell: provide genphy suspend/resume Sebastian Hesselbarth
2013-11-20 20:21 ` [PATCH RFC v1 2/7] net: phy: provide phy_resume/phy_suspend helpers Sebastian Hesselbarth
2013-11-20 20:36 ` Florian Fainelli
2013-11-20 20:21 ` [PATCH RFC v1 3/7] net: phy: resume/suspend PHYs on attach/detach Sebastian Hesselbarth
2013-11-20 20:21 ` [PATCH RFC v1 4/7] net: phy: suspend unused PHYs on mdio_bus in late_initcall Sebastian Hesselbarth
2013-11-20 20:58 ` Florian Fainelli
2013-11-20 21:05 ` Sebastian Hesselbarth
2013-11-20 22:36 ` Florian Fainelli
2013-11-20 20:21 ` [PATCH RFC v1 5/7] net: mv643xx_eth: resume/suspend PHY on port start/stop Sebastian Hesselbarth
2013-11-20 20:21 ` [PATCH RFC v1 6/7] net: mvneta: " Sebastian Hesselbarth
2013-11-20 20:21 ` [PATCH RFC v1 7/7] net: cpsw: " Sebastian Hesselbarth
2013-11-20 20:48 ` Florian Fainelli
2013-11-20 20:57 ` Sebastian Hesselbarth
2013-11-21 8:35 ` Mugunthan V N
2013-11-21 8:41 ` Sebastian Hesselbarth
2013-11-20 20:36 ` David Miller [this message]
2013-11-20 20:54 ` [PATCH RFC v1 0/7] net: phy: Ethernet PHY powerdown optimization Sebastian Hesselbarth
2013-11-20 21:10 ` Florian Fainelli
2013-11-20 21:20 ` Sebastian Hesselbarth
2013-11-20 22:15 ` David Miller
2013-12-04 15:44 ` [PATCH RFCv2 0/6] " Sebastian Hesselbarth
2013-12-05 7:57 ` Mugunthan V N
2013-12-06 0:16 ` Florian Fainelli
2013-12-08 14:40 ` [PATCH v1 " Sebastian Hesselbarth
2013-12-08 14:40 ` [PATCH v1 1/6] net: mv643xx_eth: properly start/stop phy device Sebastian Hesselbarth
2013-12-11 2:52 ` David Miller
2013-12-11 2:56 ` David Miller
2013-12-11 7:06 ` Sebastian Hesselbarth
2013-12-11 17:28 ` David Miller
2013-12-08 14:40 ` [PATCH v1 2/6] net: phy: marvell: provide genphy suspend/resume Sebastian Hesselbarth
2013-12-08 14:40 ` [PATCH v1 3/6] net: phy: provide phy_resume/phy_suspend helpers Sebastian Hesselbarth
2013-12-08 14:40 ` [PATCH v1 4/6] net: phy: resume/suspend PHYs on attach/detach Sebastian Hesselbarth
2013-12-08 14:40 ` [PATCH v1 5/6] net: phy: suspend unused PHYs on mdio_bus in late_initcall Sebastian Hesselbarth
2013-12-08 14:40 ` [PATCH v1 6/6] net: phy: suspend phydev when going to HALTED Sebastian Hesselbarth
2013-12-13 9:20 ` [PATCH v2 0/5] net: phy: Ethernet PHY powerdown optimization Sebastian Hesselbarth
2013-12-17 19:43 ` David Miller
2014-02-04 19:38 ` Sebastian Hesselbarth
2014-02-04 22:51 ` Florian Fainelli
2014-02-06 16:57 ` Ezequiel Garcia
2013-12-13 9:20 ` [PATCH v2 1/5] net: mv643xx_eth: properly start/stop phy device Sebastian Hesselbarth
2013-12-13 9:20 ` [PATCH v2 2/5] net: phy: marvell: provide genphy suspend/resume Sebastian Hesselbarth
2013-12-13 9:20 ` [PATCH v2 3/5] net: phy: provide phy_resume/phy_suspend helpers Sebastian Hesselbarth
2013-12-13 9:20 ` [PATCH v2 4/5] net: phy: resume/suspend PHYs on attach/detach Sebastian Hesselbarth
2013-12-13 9:20 ` [PATCH v2 5/5] net: phy: suspend phydev when going to HALTED Sebastian Hesselbarth
2013-12-04 15:44 ` [PATCH RFCv2 1/6] net: mv643xx_eth: properly start/stop phy device Sebastian Hesselbarth
2013-12-04 15:44 ` [PATCH RFCv2 2/6] net: phy: marvell: provide genphy suspend/resume Sebastian Hesselbarth
2013-12-04 15:44 ` [PATCH RFCv2 3/6] net: phy: provide phy_resume/phy_suspend helpers Sebastian Hesselbarth
2013-12-06 0:08 ` Florian Fainelli
2013-12-04 15:44 ` [PATCH RFCv2 4/6] net: phy: resume/suspend PHYs on attach/detach Sebastian Hesselbarth
2013-12-04 15:44 ` [PATCH RFCv2 5/6] net: phy: suspend unused PHYs on mdio_bus in late_initcall Sebastian Hesselbarth
2013-12-04 21:05 ` Sergei Shtylyov
2013-12-06 0:02 ` Florian Fainelli
2013-12-04 15:44 ` [PATCH RFCv2 6/6] net: phy: suspend phydev when going to HALTED Sebastian Hesselbarth
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