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Date:   Tue, 18 Apr 2023 09:24:50 +0200
From:   Oleksij Rempel <o.rempel@pengutronix.de>
To:     Vladimir Oltean <olteanv@gmail.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Andrew Lunn <andrew@lunn.ch>,
        Eric Dumazet <edumazet@google.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Woojung Huh <woojung.huh@microchip.com>,
        Arun Ramadoss <arun.ramadoss@microchip.com>,
        kernel@pengutronix.de, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org, UNGLinuxDriver@microchip.com
Subject: Re: [PATCH net-next v1 2/2] net: dsa: microchip: Add partial ACL
 support for ksz9477 switches
Message-ID: <20230418072450.GC30964@pengutronix.de>
References: <20230411172456.3003003-1-o.rempel@pengutronix.de>
 <20230411172456.3003003-3-o.rempel@pengutronix.de>
 <20230413042936.GA12562@pengutronix.de>
 <20230416165904.2y7zwgyxwltjzj7m@skbuf>
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On Sun, Apr 16, 2023 at 07:59:04PM +0300, Vladimir Oltean wrote:
> On Thu, Apr 13, 2023 at 06:29:36AM +0200, Oleksij Rempel wrote:
> > According to KSZ9477S 5.2.8.2 Port Priority Control Register
> > "To achieve the desired functionality, do not set more than one bit at a
> > time in this register.
> > ...
> > Bit 6 - OR’ed Priority
> > ...
> > Bit 2 - 802.1p Priority Classification
> > Bit 1 - Diffserv Priority Classification
> > Bit 0 - ACL Priority Classification
> > "
> > @Arun  what will happen if multiple engines are used for packet
> > prioritization? For example ACL || Diffserv || 802.1p... ?
> > If I see it correctly, it is possible but not recommended. Should I
> > prevent usage of multiple prio sources? 
> 
> You could try and find out which one takes priority... we support VLAN
> PCP and DSCP prioritization through the dcbnl application priority table.

What will be the mainlineable interface for the DSCP support for KSZ8 series?
If i see it correctly, it should be possible to use tc:
tc filter add dev lan2 ingress protocol ip flower ip_tos 0x28 skip_sw skbedit priority 7
or dcb:
dcb app add dev lan2 dscp-prio 28:7

dcb implementation seems to have some advantages, since it will
allow to use OpenLLDP to configure traffic priorities. Correct?

Regards,
Oleksij
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