From: Andrew Lunn <andrew@lunn.ch>
To: Alexandru Ardelean <alexandru.ardelean@analog.com>
Cc: netdev@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, davem@davemloft.net,
robh+dt@kernel.org, mark.rutland@arm.com, f.fainelli@gmail.com,
hkallweit1@gmail.com, mkubecek@suse.cz
Subject: Re: [PATCH v4 1/2] ethtool: implement Energy Detect Powerdown support via phy-tunable
Date: Sat, 14 Sep 2019 17:26:14 +0200 [thread overview]
Message-ID: <20190914152614.GJ27922@lunn.ch> (raw)
In-Reply-To: <20190912162812.402-2-alexandru.ardelean@analog.com>
On Thu, Sep 12, 2019 at 07:28:11PM +0300, Alexandru Ardelean wrote:
> The `phy_tunable_id` has been named `ETHTOOL_PHY_EDPD` since it looks like
> this feature is common across other PHYs (like EEE), and defining
> `ETHTOOL_PHY_ENERGY_DETECT_POWER_DOWN` seems too long.
>
> The way EDPD works, is that the RX block is put to a lower power mode,
> except for link-pulse detection circuits. The TX block is also put to low
> power mode, but the PHY wakes-up periodically to send link pulses, to avoid
> lock-ups in case the other side is also in EDPD mode.
>
> Currently, there are 2 PHY drivers that look like they could use this new
> PHY tunable feature: the `adin` && `micrel` PHYs.
>
> The ADIN's datasheet mentions that TX pulses are at intervals of 1 second
> default each, and they can be disabled. For the Micrel KSZ9031 PHY, the
> datasheet does not mention whether they can be disabled, but mentions that
> they can modified.
>
> The way this change is structured, is similar to the PHY tunable downshift
> control:
> * a `ETHTOOL_PHY_EDPD_DFLT_TX_MSECS` value is exposed to cover a default
> TX interval; some PHYs could specify a certain value that makes sense
> * `ETHTOOL_PHY_EDPD_NO_TX` would disable TX when EDPD is enabled
> * `ETHTOOL_PHY_EDPD_DISABLE` will disable EDPD
>
> As noted by the `ETHTOOL_PHY_EDPD_DFLT_TX_MSECS` the interval unit is 1
> millisecond, which should cover a reasonable range of intervals:
> - from 1 millisecond, which does not sound like much of a power-saver
> - to ~65 seconds which is quite a lot to wait for a link to come up when
> plugging a cable
>
> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Andrew
next prev parent reply other threads:[~2019-09-14 15:26 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-12 16:28 [PATCH v4 0/2] ethtool: implement Energy Detect Powerdown support via phy-tunable Alexandru Ardelean
2019-09-12 16:28 ` [PATCH v4 1/2] " Alexandru Ardelean
2019-09-14 15:26 ` Andrew Lunn [this message]
2019-09-15 15:08 ` Florian Fainelli
2019-09-12 16:28 ` [PATCH v4 2/2] net: phy: adin: implement Energy Detect Powerdown mode " Alexandru Ardelean
2019-09-14 15:29 ` Andrew Lunn
2019-09-15 15:11 ` Florian Fainelli
2019-09-16 6:44 ` Ardelean, Alexandru
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