Re: [PATCH v1 1/2] driver core: fw_devlink: Add support for FWNODE_FLAG_BROKEN_PARENT

From: Andrew Lunn
Date: Tue Aug 31 2021 - 18:06:11 EST

On Tue, Aug 31, 2021 at 12:26:30PM -0700, Saravana Kannan wrote:
> On Tue, Aug 31, 2021 at 6:16 AM Andrew Lunn <andrew@xxxxxxx> wrote:
> >
> > > > I must admit, my main problem at the moment is -rc1 in two weeks
> > > > time. It seems like a number of board with Ethernet switches will be
> > > > broken, that worked before. phy-handle is not limited to switch
> > > > drivers, it is also used for Ethernet drivers. So it could be, a
> > > > number of Ethernet drivers are also going to be broken in -rc1?
> > >
> > > Again, in those cases, based on your FEC example, fw_devlink=on
> > > actually improves things.
> >
> > Debatable. I did some testing. As expected some boards with Ethernet
> > switches are now broken.
> To clarify myself, I'm saying the patch to parse "ethernet" [8] will
> make things better with fw_devlink=on for FEC. Not sure if you tested
> that patch or not.

Yes and no. I was tested with the FEC, but because of fw_devlink=on,
the switches don't probe correctly. So it is not possible to see if it
helped or not, since its plain broken.

> Not sure what was the tip of the tree with which you bisected.

I manually tested linux-next, v5.14, v5.13 and v5.12 and then

$ git bisect log
git bisect start
# good: [9f4ad9e425a1d3b6a34617b8ea226d56a119a717] Linux 5.12
git bisect good 9f4ad9e425a1d3b6a34617b8ea226d56a119a717
# bad: [62fb9874f5da54fdb243003b386128037319b219] Linux 5.13

So well away from linux-next which contains the phy-handle parser.

I will try to give the two patches a try today or tomorrow.

> Thanks for testing it out. And worst case, we'll revert phy-handle
> support.

Which is not enough to fix these Ethernet switches.