Subject: Re: mvneta: comphy regression with SolidRun ClearFog

From: Russell King - ARM Linux admin <[email-masked]>
Date: Wed, 19 Feb 2020 09:22:27 +0000

On Tue, Feb 18, 2020 at 10:14:48PM -0700, Joel Johnson wrote:
> In updating recently I'm encountering a regression with the mvneta driver on
> SolidRun ClearFog Base devices. I originally filed the bug with Debian
> (https://bugs.debian.org/951409) since I was using distro provided packages,
> but after further investigation I have isolated the issue as related to
> comphy support added during development for kernel version 5.1.
> 
> When booting stock kernels up to 5.0 everything works as expected with three
> ethernet devices identified and functional. However, running any kernel 5.1
> or later, I only have a single ethernet device available. The single device
> available appears to be the one attached to the SoC itself and not connected
> via SerDes lanes using comphy, i.e. the one defined at f1070000.ethernet.
> 
> With some log/diff assisted bisecting, I've been able to confirm that the
> "tipping point" changeset is f548ced15f90, which actually performs the DT
> change for the ClearFog family of devices. That's the commit at which the
> failure starts, but is just the final enablement of the added feature in the
> overall series. I've also tested booting the same kernel binary (including
> up to v5.6-rc1) and only swapping the dtb for one excluding the problematic
> commit and confirmed that simply changing the dtb results in all three
> devices being functional, albeit obviously without comphy support.

Does debian have support for the comphy enabled in their kernel,
which is controlled by CONFIG_PHY_MVEBU_A38X_COMPHY ?

-- 
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