Re: [PATCH] net: Bring up all interfaces before going interactive

[Sascha Hauer <s.hauer@pengutronix.de>]

On Tue, Sep 20, 2022 at 02:47:07AM -0700, Trent Piepho wrote:
> On Tue, Sep 20, 2022 at 12:41 AM Sascha Hauer <s.hauer@pengutronix.de> wrote:
> > On Mon, Sep 19, 2022 at 10:20:53AM -0700, Trent Piepho wrote:
> > > On Fri, Sep 16, 2022 at 6:16 AM Sascha Hauer <s.hauer@pengutronix.de> wrote:
> > > >
> > > > We could make the user experience even a bit better by doing this call
> > > > before waiting for the autoboot timeout which then speeds up netboot a
> > > > bit.
> > >
> > > The Linux phy driver almost invariably does not bother to avoid
> > > resetting the network phy when not necessary.  So if network
> > > auto-negotiation is started in barebox, it will be reset and then
> > > restarted shortly after in Linux.  The link auto-negotiation impacts
> > > the LAN's spanning tree if that is in use.
> > >
> > > So there is a drawback, besides the small added boot time to
> > > initialize the network hardware, to adding an unneeded network restart
> > > in Barebox in the case where interactive mode is not entered and
> > > network boot is not used.
> >
> > So is this a vote to only do the autonegotiaton when going interactive
> > in barebox, or a vote to do autonegotiation only when the network is
> > being used in barebox?
> 
> I would vote to only do it when going interactive.

I changed the behaviour accordingly.

> 
> It also seems reasonable to bring the network up quickly when network
> booting, but I think determining if the system will network boot,
> before actually trying to boot, is probably unreasonably difficult to
> do.

I don't know how we could determine if we are going to do a network
boot.
We could do the network initialisation earlier based on some globalvar
like Marco suggested, but currently I do not have enough motivation to
implement it.

Sascha

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