netdev - Re: [PATCH net-next 0/5] Flow control for NXP ENETC

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Message-ID: <20210419140442.79dd0ce0@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
Date:   Mon, 19 Apr 2021 14:04:42 -0700
From:   Jakub Kicinski <kuba@...nel.org>
To:     Vladimir Oltean <olteanv@...il.com>
Cc:     "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        Po Liu <po.liu@....com>,
        Claudiu Manoil <claudiu.manoil@....com>,
        Alex Marginean <alexandru.marginean@....com>,
        Rob Herring <robh+dt@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        Russell King - ARM Linux admin <linux@...linux.org.uk>,
        Andrew Lunn <andrew@...n.ch>, Michael Walle <michael@...le.cc>,
        Vladimir Oltean <vladimir.oltean@....com>
Subject: Re: [PATCH net-next 0/5] Flow control for NXP ENETC

On Sat, 17 Apr 2021 02:42:20 +0300 Vladimir Oltean wrote:
> From: Vladimir Oltean <vladimir.oltean@....com>
> 
> This patch series contains logic for enabling the lossless mode on the
> RX rings of the ENETC, and the PAUSE thresholds on the internal FIFO
> memory.
> 
> During testing it was found that, with the default FIFO configuration,
> a sender which isn't persuaded by our PAUSE frames and keeps sending
> will cause some MAC RX frame errors. To mitigate this, we need to ensure
> that the FIFO never runs completely full, so we need to fix up a setting
> that was supposed to be configured well out of reset. Unfortunately this
> requires the addition of a new mini-driver.

FWIW back in the day when I was working on more advanced devices than 
I deal with these days I was expecting to eventually run into this as
well and create some form of devlink umbrella. IMHO such "mini driver"
is a natural place for a devlink instance, and not the PFs/ports.
Is this your thinking as well? AFAICT enetc doesn't implement devlink
today so you start from whatever model works best without worrying
about backward compat.