Re: [PATCH v3] ARM: dts: imx: Fix the AR803X phy-mode

From: "George G. Davis" <george_davis@mentor.com>
To: Sasha Levin <sashal@kernel.org>
Cc: Fabio Estevam <festevam@gmail.com>, <stable@vger.kernel.org>,
	<shawnguo@kernel.org>, <andrew@lunn.ch>, <baruch@tkos.co.il>,
	<ken.lin@advantech.com>, <smoch@web.de>,
	<stwiss.opensource@diasemi.com>, <linux-imx@nxp.com>,
	<kernel@pengutronix.de>, Marc Kleine-Budde <mkl@pengutronix.de>,
	<aford173@gmail.com>, <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v3] ARM: dts: imx: Fix the AR803X phy-mode
Date: Mon, 13 May 2019 21:16:07 -0400	[thread overview]
Message-ID: <20190514011606.GA18528@mam-gdavis-lt> (raw)
In-Reply-To: <20190514004539.GG11972@sasha-vm>

On Mon, May 13, 2019 at 08:45:39PM -0400, Sasha Levin wrote:
> On Mon, May 13, 2019 at 01:18:27PM -0400, George G. Davis wrote:
> >Hello,
> >
> >On Wed, Apr 03, 2019 at 07:12:41PM -0300, Fabio Estevam wrote:
> >>Commit 6d4cd041f0af ("net: phy: at803x: disable delay only for RGMII mode")
> >>exposed an issue on imx DTS files using AR8031/AR8035 PHYs.
> >>
> >>The end result is that the boards can no longer obtain an IP address
> >>via UDHCP, for example.
> >>
> >>Quoting Andrew Lunn:
> >>
> >>"The problem here is, all the DTs were broken since day 0. However,
> >>because the PHY driver was also broken, nobody noticed and it
> >>worked. Now that the PHY driver has been fixed, all the bugs in the
> >>DTs now become an issue"
> >>
> >>To fix this problem, the phy-mode property needs to be "rgmii-id",  which
> >>has the following meaning as per
> >>Documentation/devicetree/bindings/net/ethernet.txt:
> >>
> >>"RGMII with internal RX and TX delays provided by the PHY, the MAC should
> >>not add the RX or TX delays in this case)"
> >>
> >>Tested on imx6-sabresd, imx6sx-sdb and imx7d-pico boards with
> >>successfully restored networking.
> >>
> >>Based on the initial submission from Steve Twiss for the
> >>imx6qdl-sabresd.
> >>
> >>Signed-off-by: Fabio Estevam <festevam@gmail.com>
> >>Tested-by: Baruch Siach <baruch@tkos.co.il>
> >>Tested-by: Soeren Moch <smoch@web.de>
> >>Tested-by: Steve Twiss <stwiss.opensource@diasemi.com>
> >>Tested-by: Adam Thomson <Adam.Thomson@diasemi.com>
> >>Signed-off-by: Steve Twiss <stwiss.opensource@diasemi.com>
> >>Tested-by: Marc Kleine-Budde <mkl@pengutronix.de>
> >>Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
> >>---
> >>Changes since v2:
> >>- Also fixed imx6q-ba16
> >>- Removed stable tag as it does not apply cleanly on older
> >>stable trees. I can manually generate versions for stable
> >>trees after this one hits mainline.
> >
> >Please add this commit to the v5.1.x stable queue to resolve NFS root breakage
> >in v5.1. I can confirm that it applies cleanly to v5.1.1 and resolves NFS root
> >breakage that occurs on i.MX6 boards in v5.1.x, tested on imx6q-sabreauto.dts
> >and imx6q-sabresd.dts. Although the fix should be backported to pre-v5.1.x
> >stable series as well, it does not cause problems for pre-v5.1 but results in
> >NFS root breakage for v5.1.x.
> 
> What's the commit id in Linus's tree? I don't see it.

Er, um, sorry, it was deferred to linux-next commit 68e9c97161b3 ("serial:
sh-sci: disable DMA for uart_console"), which quite frankly rather annoyed me
personally since linux-next commit 68e9c97161b3 is required to fix a regression
caused by v5.1 commit 6d4cd041f0af. In my opinion, linux-next commit
68e9c97161b3 really should have been pushed to the v5.1 release, earlier, due
to the noted regression, but I'm happy to wait for linux-next commit
68e9c97161b3 to make it to Linus's tree before propagating it to linux-stable.
Meanwhile, I wanted to let you know that v5.1.x is rather broken, in this
regard, on i.MX6 as-is for now.

> 
> --
> Thanks,
> Sasha

-- 
Regards,
George