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

From: Sasha Levin <sashal@kernel.org>
To: "George G. Davis" <george_davis@mentor.com>
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 22:07:42 -0400	[thread overview]
Message-ID: <20190514020742.GJ11972@sasha-vm> (raw)
In-Reply-To: <20190514011606.GA18528@mam-gdavis-lt>

On Mon, May 13, 2019 at 09:16:07PM -0400, George G. Davis wrote:
>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.

We'll happily take it once it makes it into Linus's tree and into a
release.

>Meanwhile, I wanted to let you know that v5.1.x is rather broken, in this
>regard, on i.MX6 as-is for now.

This would be something we can't do much about, but given it's an
important fix it should make it into Linus's tree very soon, right?

--
Sasha