RE: [PATCH net] net: phy: Micrel KSZ8061: fix errata solution not taking effect problem

From: Tristram.Ha
Date: Thu May 30 2024 - 18:42:45 EST


> Subject: Re: [PATCH net] net: phy: Micrel KSZ8061: fix errata solution not taking effect
> problem
>
> On Tue, 2024-05-28 at 14:37 -0700, Tristram.Ha@xxxxxxxxxxxxx wrote:
> > From: Tristram Ha <tristram.ha@xxxxxxxxxxxxx>
> >
> > KSZ8061 needs to write to a MMD register at driver initialization to fix
> > an errata. This worked in 4.14 kernel but not in newer kernels. The
> > issue is the main phylib code no longer resets PHY at the very beginning.
> > Calling phy resuming code later will reset the chip if it is already
> > powered down at the beginning. This wipes out the MMD register write.
> > Solution is to implement a phy resume function for KSZ8061 to take care
> > of this problem.
> >
> > Fixes: 232ba3a51cc2 ("net: phy: Micrel KSZ8061: link failure after cable connect")
>
> As the blamed commit belongs to 5.0 and the changelog hints anything
> after 4.14 is broken, it looks like there is an inconsistency. Please
> fix the changelog or the tag.

A customer reported this problem and said they were using 4.14 and cited
this commit, so I assumed it was added in that kernel. Indeed 4.19
kernel has this code, so it was probably backported.

I will update the comment.