On 11/09/2017 05:06 PM, Andrew Lunn wrote: > On Thu, Nov 09, 2017 at 03:03:16PM -0800, Florian Fainelli wrote: >> On 11/09/2017 02:37 PM, Andrew Lunn wrote: >>> On Thu, Nov 09, 2017 at 02:26:04PM -0800, Florian Fainelli wrote: >>>> In preparation for enabling Broadcom tags with b53, pad packets to a >>>> minimum size of 64 bytes (sans FCS) in order for the Broadcom switch to >>>> accept ingressing frames. Without this, we would typically be able to >>>> DHCP, but not resolve with ARP because packets are too small and get >>>> rejected by the switch. >>> >>> Hi Florian >>> >>> Is the MAC sending runt packets in its default configuration? Is this >>> a general issue, and not just an issue when there is a switch directly >>> attached? >> >> The MAC is sending 64 bytes (with FCS) padded packets by default, but >> this apparently gets mis-calculated when Broadcom tags are enabled, such >> that we need to pad before to avoid that. > > Hi Florian > > Ah, so maybe when the tag is stripped off it then becomes a runt > packet and so gets dropped.
Yes, that is exactly what I observed. -- Florian
