Re: [PATCH] net: uclass: Save ethernet MAC address when generated

[Tom Rini <trini@konsulko.com>]

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On Thu, Nov 04, 2021 at 12:18:46PM +0100, Michal Simek wrote:
> 
> 
> On 11/3/21 17:57, Tom Rini wrote:
> > On Tue, Nov 02, 2021 at 11:27:22AM +0100, Michal Simek wrote:
> > > 
> > > 
> > > On 11/2/21 10:00, Michael Walle wrote:
> > > > > On Fri, Oct 29, 2021 at 2:14 PM Michal Simek <michal.simek@xilinx.com> wrote:
> > > > > > 
> > > > > > When MAC address is randomly generated it should be also saved to
> > > > > > variables. This step is there when MAC address is passed via pdata but not
> > > > > > when it is randomly generated.
> > > > > > 
> > > > > > Signed-off-by: Michal Simek <michal.simek@xilinx.com>
> > > > > > ---
> > > > > > 
> > > > > >    net/eth-uclass.c | 2 ++
> > > > > >    1 file changed, 2 insertions(+)
> > > > > > 
> > > > > > diff --git a/net/eth-uclass.c b/net/eth-uclass.c
> > > > > > index 0da0e85be031..58c308f33276 100644
> > > > > > --- a/net/eth-uclass.c
> > > > > > +++ b/net/eth-uclass.c
> > > > > > @@ -583,6 +583,8 @@ static int eth_post_probe(struct udevice *dev)
> > > > > >                   net_random_ethaddr(pdata->enetaddr);
> > > > > >                   printf("\nWarning: %s (eth%d) using random MAC address - %pM\n",
> > > > > >                          dev->name, dev_seq(dev), pdata->enetaddr);
> > > > > > +               eth_env_set_enetaddr_by_index("eth", dev_seq(dev),
> > > > > > +                                             pdata->enetaddr);
> > > > > >    #else
> > > > > >                   printf("\nError: %s address not set.\n",
> > > > > >                          dev->name);
> > > > > > --
> > > > > > 2.33.1
> > > > > > 
> > > > > Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
> > > > 
> > > > Please note, that this will change behavior. Before this commit, the
> > > > random mac address was local to u-boot (at least for most network drivers).
> > > > After this commit, it will also be communicated to linux.
> > > > 
> > > > I'm not sure what to think of this. At the very least, this should be
> > > > documented in the commit message and in the Kconfig help text.
> > > 
> > > Thanks for bringing this up. I have no issue that this address is being
> > > propagated to Linux but others can feel this as an issue.
> > > I can definitely extend commit message to say it.
> > > 
> > > I found this via net list command where you can see controllers but you
> > > can't see their mac addresses which is IMHO wrong.
> > 
> > So, this causes dhcp to simply timeout for me on a pine64_plus board
> > (where yes, I believe we do end up using a random MAC) when running the
> > pytest suite.  I wonder if this particular change messes up the state
> > machine?  Checking the dnsmasq logs it looks like U-Boot keeps asking
> > and getting a reply, over and over.
> 
> It is just saving that values to variables. If you want to propagete that
> values in the stack that's up to your system configuration.
> 
> What state machine are you talking about?

I was just making a guess about state machine, given what I had recalled
of the network stack before.  To be clearer, I bisected down my failure
of 3 tests that run "setenv autoload no ; dhcp" and then dhcp timing
out, to this commit (in the network PR).

-- 
Tom

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