linux-kernel - Re: [PATCH v1 net] net: mscc: ocelot: remove buggy and useless write to ANA_PFC_PFC

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Message-ID: <20210916114917.aielkefz5gg7flto@skbuf>
Date:   Thu, 16 Sep 2021 11:49:18 +0000
From:   Vladimir Oltean <vladimir.oltean@....com>
To:     Colin Foster <colin.foster@...advantage.com>
CC:     Claudiu Manoil <claudiu.manoil@....com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        "UNGLinuxDriver@...rochip.com" <UNGLinuxDriver@...rochip.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 net] net: mscc: ocelot: remove buggy and useless write
 to ANA_PFC_PFC_CFG

On Wed, Sep 15, 2021 at 06:09:37PM -0700, Colin Foster wrote:
> A useless write to ANA_PFC_PFC_CFG was left in while refactoring ocelot to
> phylink. Since priority flow control is disabled, writing the speed has no
> effect.
> 
> Further, it was using ethtool.h SPEED_ instead of OCELOT_SPEED_ macros,
> which are incorrectly offset for GENMASK.
> 
> Lastly, for priority flow control to properly function, some scenarios
> would rely on the rate adaptation from the PCS while the MAC speed would
> be fixed. So it isn't used, and even if it was, neither "speed" nor
> "mac_speed" are necessarily the correct values to be used.
> 
> Fixes: e6e12df625f2 ("net: mscc: ocelot: convert to phylink")
> Signed-off-by: Colin Foster <colin.foster@...advantage.com>
> ---
>  drivers/net/ethernet/mscc/ocelot.c | 4 ----
>  1 file changed, 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
> index c581b955efb3..08be0440af28 100644
> --- a/drivers/net/ethernet/mscc/ocelot.c
> +++ b/drivers/net/ethernet/mscc/ocelot.c
> @@ -569,10 +569,6 @@ void ocelot_phylink_mac_link_up(struct ocelot *ocelot, int port,
>  	ocelot_port_writel(ocelot_port, DEV_CLOCK_CFG_LINK_SPEED(speed),
>  			   DEV_CLOCK_CFG);
>  
> -	/* No PFC */
> -	ocelot_write_gix(ocelot, ANA_PFC_PFC_CFG_FC_LINK_SPEED(speed),
> -			 ANA_PFC_PFC_CFG, port);
> -

This will conflict with the other patch.... why didn't you send both as
part of a series? By not doing that, you are telling patchwork to
build-test them in parallel, which of course does not work:
https://patchwork.kernel.org/project/netdevbpf/patch/20210916012341.518512-1-colin.foster@in-advantage.com/

Also, why didn't you bump the version counter of the patch, and we're
still at v1 despite the earlier attempt?

git format-patch -2 --cover-letter --subject-prefix="PATCH v3 net" -o /opt/patches/linux/ocelot-phylink-fixes/v3/
./scripts/get_maintainer.pl /opt/patches/linux/ocelot-phylink-fixes/v3/*.patch
./scripts/checkpatch.pl --strict /opt/patches/linux/ocelot-phylink-fixes/v3/*.patch
# Go through patches, write change log compared to v2 using vimdiff, meld, git range-diff, whatever
# Write cover letter summarizing what changes and why. If fixing bugs explain the impact.
git send-email \
	--to='netdev@...r.kernel.org' \
	--to='linux-kernel@...r.kernel.org' \
	--cc='Vladimir Oltean <vladimir.oltean@....com>' \
	--cc='Claudiu Manoil <claudiu.manoil@....com>' \
	--cc='Alexandre Belloni <alexandre.belloni@...tlin.com>' \
	--cc='UNGLinuxDriver@...rochip.com' \
	--cc='"David S. Miller" <davem@...emloft.net>' \
	--cc='Jakub Kicinski <kuba@...nel.org>' \
	/opt/patches/linux/ocelot-phylink-fixes/v3/*.patch

Reviewed-by: Vladimir Oltean <vladimir.oltean@....com>

Please keep this tag but resend a new version. You can download the patch with the review tags automatically using:
git b4 20210916010938.517698-1-colin.foster@...advantage.com
git b4 20210916012341.518512-1-colin.foster@...advantage.com

where "git b4" is an alias configured like this in ~/.gitconfig:

[b4]
	midmask = https://lore.kernel.org/r/%s
[alias]
	b4 = "!f() { b4 am -t -o - $@ | git am -3; }; f"