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From:   Shenwei Wang <shenwei.wang@nxp.com>
To:     Russell King <linux@armlinux.org.uk>,
        Johannes Zink <j.zink@pengutronix.de>
CC:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Neil Armstrong <neil.armstrong@linaro.org>,
        Kevin Hilman <khilman@baylibre.com>,
        Vinod Koul <vkoul@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Samuel Holland <samuel@sholland.org>,
        Giuseppe Cavallaro <peppe.cavallaro@st.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Jose Abreu <joabreu@synopsys.com>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        dl-linux-imx <linux-imx@nxp.com>,
        Jerome Brunet <jbrunet@baylibre.com>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        Bhupesh Sharma <bhupesh.sharma@linaro.org>,
        Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>,
        Simon Horman <simon.horman@corigine.com>,
        Andrew Halaney <ahalaney@redhat.com>,
        Bartosz Golaszewski <bartosz.golaszewski@linaro.org>,
        Wong Vee Khee <veekhee@apple.com>,
        Revanth Kumar Uppala <ruppala@nvidia.com>,
        Jochen Henneberg <jh@henneberg-systemdesign.com>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
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        "imx@lists.linux.dev" <imx@lists.linux.dev>,
        Frank Li <frank.li@nxp.com>
Subject: RE: [EXT] Re: [PATCH v3 net 2/2] net: stmmac: dwmac-imx: pause the
 TXC clock in fixed-link
Thread-Topic: [EXT] Re: [PATCH v3 net 2/2] net: stmmac: dwmac-imx: pause the
 TXC clock in fixed-link
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Date:   Tue, 1 Aug 2023 17:06:46 +0000
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> -----Original Message-----
> From: Russell King <linux@armlinux.org.uk>
> Sent: Tuesday, August 1, 2023 7:57 AM
> To: Johannes Zink <j.zink@pengutronix.de>
> Cc: Shenwei Wang <shenwei.wang@nxp.com>; David S. Miller
> <davem@davemloft.net>; Eric Dumazet <edumazet@google.com>; Jakub
> Kicinski <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; Maxime
> Coquelin <mcoquelin.stm32@gmail.com>; Shawn Guo <shawnguo@kernel.org>;
> Sascha Hauer <s.hauer@pengutronix.de>; Neil Armstrong
> <neil.armstrong@linaro.org>; Kevin Hilman <khilman@baylibre.com>; Vinod
> Koul <vkoul@kernel.org>; Chen-Yu Tsai <wens@csie.org>; Jernej Skrabec
> <jernej.skrabec@gmail.com>; Samuel Holland <samuel@sholland.org>;
> Giuseppe Cavallaro <peppe.cavallaro@st.com>; Alexandre Torgue
> <alexandre.torgue@foss.st.com>; Jose Abreu <joabreu@synopsys.com>;
> Pengutronix Kernel Team <kernel@pengutronix.de>; Fabio Estevam
> <festevam@gmail.com>; dl-linux-imx <linux-imx@nxp.com>; Jerome Brunet
> <jbrunet@baylibre.com>; Martin Blumenstingl
> <martin.blumenstingl@googlemail.com>; Bhupesh Sharma
> <bhupesh.sharma@linaro.org>; Nobuhiro Iwamatsu
> <nobuhiro1.iwamatsu@toshiba.co.jp>; Simon Horman
> <simon.horman@corigine.com>; Andrew Halaney <ahalaney@redhat.com>;
> Bartosz Golaszewski <bartosz.golaszewski@linaro.org>; Wong Vee Khee
> <veekhee@apple.com>; Revanth Kumar Uppala <ruppala@nvidia.com>; Jochen
> Henneberg <jh@henneberg-systemdesign.com>; netdev@vger.kernel.org; linux-
> stm32@st-md-mailman.stormreply.com; linux-arm-kernel@lists.infradead.org;
> linux-kernel@vger.kernel.org; linux-amlogic@lists.infradead.org;
> imx@lists.linux.dev; Frank Li <frank.li@nxp.com>
> Subject: [EXT] Re: [PATCH v3 net 2/2] net: stmmac: dwmac-imx: pause the T=
XC
> clock in fixed-link
>
> Caution: This is an external email. Please take care when clicking links =
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> opening attachments. When in doubt, report the message using the 'Report =
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> email' button
>
>
> On Tue, Aug 01, 2023 at 02:47:46PM +0200, Johannes Zink wrote:
> > Hi Shenwei,
> >
> > thanks for your patch.
> >
> > On 7/31/23 18:19, Shenwei Wang wrote:
> > > When using a fixed-link setup, certain devices like the SJA1105
> > > require a small pause in the TXC clock line to enable their internal
> > > tunable delay line (TDL).
> >
> > If this is only required for some devices, is it safe to enforce this
> > behaviour unconditionally for any kind of fixed link devices connected
> > to the MX93 EQOS or could this possibly break for other devices?
>
> This same point has been raised by Andrew Halaney in message-id
> <4govb566nypifbtqp5lcbsjhvoyble5luww3onaa2liinboguf@4kgihys6vhrg>
> and Fabio Estevam in message-id
>
> <CAOMZO5ANQmVbk_jy7qdVtzs3716FisT2c72W+3WZyu7FoAochw@mail.gmail.
> com>
> but we don't seem to have any answer for it.
>
Hi Russell,

I hope you have thoroughly read all of my earlier responses, as I believe I=
 already addressed this question.
I'm happy to clarify further, but kindly avoid unsubstantiated comments.

https://lore.kernel.org/imx/20230727152503.2199550-1-shenwei.wang@nxp.com/T=
/#m08da3797a056d4d8ea4c1d8956b445ae967e7cfa
" Yes, that's the purpose because it won't hurt even the other side is not =
SJA1105."

> Also, the patch still uses wmb() between the write and the delay, and as =
Will
> Deacon pointed out in his message, message-id
> <20230728153611.GH21718@willie-the-truck>
> this is not safe, yet still a new version was sent.
>

Can we conclude that even without the wmb() here, the desired delay time be=
tween
operations can still be ensured?

Thanks,
Shenwei

> It seems the author of these patches is pretty resistant to comments, and=
 has
> shown that when I was requesting changes - it was an awful struggle to ge=
t
> changes made. I'm now of the opinion that I really can't be bothered to r=
eview
> these patches, precisely because feedback is clearly not welcome or if we=
lcome,
> apparently acted upon.
>
> --
> RMK's Patch system:
> https://www.ar/
> mlinux.org.uk%2Fdeveloper%2Fpatches%2F&data=3D05%7C01%7Cshenwei.wang
> %40nxp.com%7Ce65ab380ff5b4748da5308db928ec751%7C686ea1d3bc2b4c6fa
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