Re: [PATCH] Revert "ARM: dts: sun7i: A20-olinuxino-lime2: Fix ethernet phy-mode"

From: Corentin Labbe <clabbe.montjoie@gmail.com>
To: "Petr Štetiar" <ynezz@true.cz>
Cc: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Maxime Ripard" <mripard@kernel.org>,
	"Bastien Roucariès" <rouca@debian.org>,
	"Chen-Yu Tsai" <wens@csie.org>,
	"Jernej Skrabec" <jernej.skrabec@gmail.com>,
	"Rob Herring" <robh+dt@kernel.org>,
	stable@vger.kernel.org, devicetree@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Revert "ARM: dts: sun7i: A20-olinuxino-lime2: Fix ethernet phy-mode"
Date: Tue, 15 Mar 2022 08:37:06 +0100	[thread overview]
Message-ID: <YjBCImqGsbIZ3IF4@Red> (raw)
In-Reply-To: <20220315072846.GA9129@meh.true.cz>

Le Tue, Mar 15, 2022 at 08:28:58AM +0100, Petr Štetiar a écrit :
> Petr Štetiar <ynezz@true.cz> [2022-03-08 13:55:30]:
> 
> Hi Greg,
> 
> one week has passed and as I didn't received any feedback, I'm providing more
> details in a hope to make it more clear, why I think, that this fix is wrong
> and should be reverted in LTS kernels 5.10 and 5.15.
> 
> > This reverts commit 55dd7e059098ce4bd0a55c251cb78e74604abb57 as it breaks
> > network on my A20-olinuxino-lime2 hardware revision "K" which has Micrel
> > KSZ9031RNXCC-TR Gigabit PHY. Bastien has probably some previous hardware
> > revisions which were based on RTL8211E-VB-CG1 PHY and thus this fix was
> > working on his board.
> 
> Disclaimer, I don't own A20-olinuxino-lime2 board with earlier HW revisions
> G/G1/G2 utilizing RTL8211E PHY.
> 
> My understanding is, that up to kernel version 5.9 and specifically commit
> bbc4d71d6354 ("net: phy: realtek: fix rtl8211e rx/tx delay config") it was
> likely possible to use same DTS for A20-olinuxino-lime2 with KSZ9031 or
> RTL8211E PHYs (all HW revisions).
> 
> At least I was using my A20-olinuxino-lime2 HW revision K with KSZ9031 PHY
> just fine with 4.19 kernel. After upgrade to 5.10 LTS kernel my network
> stopped working, reverting stable backport commit a90398438517 ("ARM: dts:
> sun7i: A20-olinuxino-lime2: Fix ethernet phy-mode") fixed it.
> 
> From my POV proper fix for earlier HW revisions G/G1/G2 is introduction of
> sun7i-a20-olinuxino-lime2-revG.dts with a proper `phy-mode` for RTL8211E PHY.
> 
> Cheers,
> 
> Petr
> 

Hello

If your patch is applied, older revisions will stop working, right ?

What about adding a new dtb like sun7i-a20-olinuxino-lime2-revk.dts ?

Regards

> > Cc: stable@vger.kernel.org
> > Cc: Bastien Roucariès <rouca@debian.org>
> > References: https://github.com/openwrt/openwrt/issues/9153
> > References: https://github.com/OLIMEX/OLINUXINO/blob/master/HARDWARE/A20-OLinuXino-LIME2/hardware_revision_changes_log.txt
> > Signed-off-by: Petr Štetiar <ynezz@true.cz>
> > ---
> >  arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts b/arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts
> > index ecb91fb899ff..8077f1716fbc 100644
> > --- a/arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts
> > +++ b/arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts
> > @@ -112,7 +112,7 @@ &gmac {
> >  	pinctrl-names = "default";
> >  	pinctrl-0 = <&gmac_rgmii_pins>;
> >  	phy-handle = <&phy1>;
> > -	phy-mode = "rgmii-id";
> > +	phy-mode = "rgmii";
> >  	status = "okay";
> >  };
> 