From: Andrew Lunn <andrew@lunn•ch>
To: "Russell King (Oracle)" <linux@armlinux•org.uk>
Cc: Heiner Kallweit <hkallweit1@gmail•com>,
"David S. Miller" <davem@davemloft•net>,
netdev@vger•kernel.org, Marek Beh__n <kabel@kernel•org>,
Jakub Kicinski <kuba@kernel•org>
Subject: Re: [PATCH net-next] net: phy: marvell10g: add downshift tunable support
Date: Sun, 26 Sep 2021 17:24:06 +0200 [thread overview]
Message-ID: <YVCQlul6Ar4fVtns@lunn.ch> (raw)
In-Reply-To: <YUxTvC9QVI5bGLuF@shell.armlinux.org.uk>
> So, some further questions: should we be calling the set_downshift
> implementation from the .config_init as the Marvell driver does to
> ensure that downshift is correctly enabled?
The bootloader might of messed it up, so it does not seem unreasonable
to set it somewhere at startup.
> Is .config_init really
> the best place to do this? So many things with Marvell PHYs seem to
> require a reset, which bounces the link. So if one brings up the
> network interface, then sets EEE (you get a link bounce) and then
> set downshift, you get another link bounce. Each link bounce takes
> more than a second, which means the more features that need to be
> configured after bringing the interface up, the longer it takes for
> the network to become usable. Note that Marvell downshift will cause
> the link to bounce even if the values programmed into the register
> were already there - there is no check to see if we actually changed
> anything before calling genphy_soft_reset() which seems suboptimal
> given that we have phy_modify_changed() which can tell us that.
This can clearly be optimized. Add a test if the values are being
changed. Skip the reset if it is being done as part of .config_init
and there is a guarantee a later stage will perform the reset, etc.
Andrew
prev parent reply other threads:[~2021-09-26 15:24 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-17 13:48 [PATCH net-next] net: phy: marvell10g: add downshift tunable support Russell King
2021-09-17 14:45 ` Andrew Lunn
2021-09-17 14:58 ` Russell King (Oracle)
2021-09-22 12:00 ` Russell King (Oracle)
2021-09-22 23:56 ` Andrew Lunn
2021-09-23 10:15 ` Russell King (Oracle)
2021-09-26 15:24 ` Andrew Lunn [this message]
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