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Date: Sun, 24 Mar 2024 14:45:11 +0300
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Subject: Re: [PATCH 0/3] Fix EEE support for MT7531 and MT7988 SoC switch
To: "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc: Florian Fainelli <f.fainelli@gmail.com>,
 Daniel Golle <daniel@makrotopia.org>, Andrew Lunn <andrew@lunn.ch>,
 DENG Qingfang <dqfext@gmail.com>, Sean Wang <sean.wang@mediatek.com>,
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 =?UTF-8?Q?Ren=C3=A9_van_Dorst?= <opensource@vdorst.com>,
 SkyLake Huang <SkyLake.Huang@mediatek.com>,
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 Bartel Eerdekens <bartel.eerdekens@constell8.be>, mithat.guner@xeront.com,
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References: <20240318-for-net-mt7530-fix-eee-for-mt7531-mt7988-v>
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 <38798882-c033-4949-9446-4c6f15c25ebe@gmail.com>
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On 24.03.2024 14:39, Russell King (Oracle) wrote:
> On Sun, Mar 24, 2024 at 12:47:08PM +0300, Arınç ÜNAL wrote:
>> I've tested with switch ports interfaces' tx-timer from 0 to 40, same
>> tx-timer for both interfaces. Loss is still there.
> 
> EEE implementations tend to be a mess in the way drivers implement the
> API, so one can't at the moment rely on what ethtool says about the
> status. Sadly, this is what happens when driver authors are left to
> their own ends. :(
> 
>> I suppose the MT7531 switch PHYs need calibration for EEE that is currently
>> missing from the mediatek-ge driver.
> 
> EEE is quite simple from the software point of view. There is software
> negotiation of the modules that EEE supports, and then there is are
> one or more timers that affect the behaviour of EEE. The LPI timer is
> "how long the link needs to be idle for before _this_ end signals that
> it _can_ enter low power state". The link only enters low power state
> when *both* ends of the link signal that they can enter low power
> state.
> 
> What calibration would be necessary?

Check out mt798x_phy_eee() on drivers/net/phy/mediatek-ge-soc.c.

Arınç