Subject: Re: [PATCH RFC 2/2] net: dsa: bcm_sf2: implement HW bridging operations

From: Guenter Roeck <[email-masked]>
Date: Thu, 19 Feb 2015 19:55:14 -0800

On Fri, Feb 20, 2015 at 03:02:41AM +0100, Andrew Lunn wrote:
> > Not sure yet what to do about setting the fdb aging time. I don't
> > see a mechanism to do that. No idea how important that is.
> 
> Hi Guenter
> 
> I don't know about your chip, but the public data sheet for the
> 88e6060 talks about being able to set the age time globally in the ATU
> control register. The granularity is not so good, multiple of 16
> seconds, so it could be the hardware bridge times out an entry faster
> than the software bridge.
> 
Yes, but only if the minimum is configured. The default is about 5.5
minutes on mv88e6352. I didn't check the default on the other 886exxx
chips, but I assume it is the same.

Problem is topology changes or non-standard aging times. Maybe fdb flush
on port status changes takes care of those cases; I am just not sure if
that is sufficient.

Guenter