RE: [EXT] Re: [PATCH v2 RFC net-next 08/18] net: mvpp2: add FCA periodic timer configurations

Stefan Chulski
2021-01-25T08:27:20Z

> > >
> > > --------------------------------------------------------------------
> > > -- On Sun, Jan 24, 2021 at 01:43:57PM +0200, stefanc@marvell.com
> > > wrote:
> > > > +/* Set Flow Control timer x140 faster than pause quanta to ensure
> > > > +that link
> > > > + * partner won't send taffic if port in XOFF mode.
> > >
> > > Can you explain more why 140 times faster is desirable here? Why 140
> > > times and not, say, 10 times faster? Where does this figure come
> > > from, and what is the reasoning? Is there a switch that requires it?
> >
> > I tested with 140.
> > Actually regarding to spec each quanta should be equal to 512 bit times.
> > In 10G bit time is 0.1ns.
>
> And if the link has been negotiated to 10Mbps? Or is the clock already scaled
> to the link speed?
>
> Andrew

Currently its static, probably I can add function that reconfigure timer during runtime(based on link speed).
Should it be part of this series or add it afterwards?

Regards,
Stefan.