Subject: Re: [RFC 0/2 net-next] net: dsa: MT7628 embedded switch initial support

From: Joris Vaišvila <[email-masked]>
Date: Sun, 1 Mar 2026 15:13:28 +0200

Hi Vladimir,
Thank you for the feedback.

On Sun, Mar 01, 2026 at 02:36:19PM +0200, Vladimir Oltean wrote:
> I see a slight discrepancy between what the documentation claims the
> hardware does, and what the driver claims it does. The documentation
> seems to say that setting this bit is what allows the vlan->untag bits
> to take effect.

The comment was referencing an accidentally deleted line that enables
double tagging:

	/* set up switch for double tagging to simulate vlan unawareness */
	regmap_set_bits(esw->regmap, MT7628_ESW_REG_SGC2,
			FIELD_PREP(MT7628_ESW_SGC2_DOUBLE_TAG_EN,
			MT7628_ESW_PORTS_NOCPU));

I only re-tested untagged traffic before sending this in. Apologies for
that. I will expand my testing procedures to prevent this from happening
again.

> A VLAN-unaware port means that when an ingress packet comes with 802.1Q
> TPID 0x8100 and VID X from the wire, this VLAN header will be ignored by
> the switch, and the PVID of the port will be pushed as an outer tag, for
> any value of X, regardless of whether it is in the VLAN table or not.
> Does it do that?

That is what is intended to happen and it does do that if the
DOUBLE_TAG_EN is properly set. Will be fixed in later revisions.