Re: Re: Re: Re: [PATCH net-next v4 11/11] net: dsa: realtek: rtl8365mb: multiple cpu ports, non cpu extint

Andrew Lunn
2022-01-18T13:21:03Z

On Tue, Jan 18, 2022 at 01:58:39AM -0300, Luiz Angelo Daros de Luca wrote:
> > the problem is checksum offloading on the gmac (soc-side)
>
> I suggested it might be checksum problem because I'm also affected. In
> my case, I have an mt7620a SoC connected to the rtl8367s switch. The
> OS offloads checksum to HW but the mt7620a cannot calculate the
> checksum with the (EtherType) Realtek CPU Tag in place. I'll try to
> move the CPU tag to test if the mt7620a will then digest the frame
> correctly.

Some MAC hardware you can tell it where the ether type value is in the
frame. This is often used to skip over the VLAN header, but it can
also be used to skip DSA headers. Check the datasheet for the hardware
and see if there is anything like that.

Andrew