Re: [PATCH net v2 2/2] net: dsa: mt7530: fix disabling EEE on failure on MT7531 and MT7988

From: Paolo Abeni <pabeni@redhat.com>
To: arinc.unal@arinc9.com, "Daniel Golle" <daniel@makrotopia.org>,
	"DENG Qingfang" <dqfext@gmail.com>,
	"Sean Wang" <sean.wang@mediatek.com>,
	"Andrew Lunn" <andrew@lunn.ch>,
	"Florian Fainelli" <f.fainelli@gmail.com>,
	"Vladimir Oltean" <olteanv@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	"Eric Dumazet" <edumazet@google.com>,
	"Jakub Kicinski" <kuba@kernel.org>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	"AngeloGioacchino Del Regno"
	<angelogioacchino.delregno@collabora.com>,
	"René van Dorst" <opensource@vdorst.com>,
	"Russell King" <linux@armlinux.org.uk>,
	"SkyLake Huang" <SkyLake.Huang@mediatek.com>,
	"Heiner Kallweit" <hkallweit1@gmail.com>
Cc: Bartel Eerdekens <bartel.eerdekens@constell8.be>,
	mithat.guner@xeront.com,  erkin.bozoglu@xeront.com,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	 linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org
Subject: Re: [PATCH net v2 2/2] net: dsa: mt7530: fix disabling EEE on failure on MT7531 and MT7988
Date: Tue, 26 Mar 2024 10:02:54 +0100	[thread overview]
Message-ID: <799572b672ea8b4756236b14068aef7c8fa726a6.camel@redhat.com> (raw)
In-Reply-To: <20240321-for-net-mt7530-fix-eee-for-mt7531-mt7988-v2-2-9af9d5041bfe@arinc9.com>

On Thu, 2024-03-21 at 19:29 +0300, Arınç ÜNAL via B4 Relay wrote:
> From: Arınç ÜNAL <arinc.unal@arinc9.com>
> 
> The MT7531_FORCE_EEE1G and MT7531_FORCE_EEE100 bits let the
> PMCR_FORCE_EEE1G and PMCR_FORCE_EEE100 bits determine the 1G/100 EEE
> abilities of the MAC. If MT7531_FORCE_EEE1G and MT7531_FORCE_EEE100 are
> unset, the abilities are left to be determined by PHY auto polling.
> 
> The commit 40b5d2f15c09 ("net: dsa: mt7530: Add support for EEE features")
> made it so that the PMCR_FORCE_EEE1G and PMCR_FORCE_EEE100 bits are set on
> mt753x_phylink_mac_link_up(). But it did not set the MT7531_FORCE_EEE1G and
> MT7531_FORCE_EEE100 bits. Because of this, EEE will be enabled on the
> switch MACs by polling the PHY, regardless of the result of phy_init_eee().
> 
> Define these bits and add them to MT7531_FORCE_MODE which is being used by
> the subdriver. With this, EEE will be prevented from being enabled on the
> switch MACs when phy_init_eee() fails.
> 
> Fixes: 40b5d2f15c09 ("net: dsa: mt7530: Add support for EEE features")
> Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>

If I read the past discussion correctly, this is a potential issue
found by code inspection and never producing problem in practice, am I
correct?

If so I think it will deserve a 3rd party tested-by tag or similar to
go in.

If nobody could provide such feedback in a little time, I suggest to
drop this patch and apply only 1/2.

Cheers,

Paolo

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