[PATCH v3 net 2/2] net: stmmac: dwmac-imx: pause the TXC clock in fixed-link

Russell King (Oracle) linux at armlinux.org.uk
Tue Aug 1 05:56:40 PDT 2023


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 at 4kgihys6vhrg>
and Fabio Estevam in message-id
 <CAOMZO5ANQmVbk_jy7qdVtzs3716FisT2c72W+3WZyu7FoAochw at mail.gmail.com>
but we don't seem to have any answer for it.

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 at willie-the-truck>
this is not safe, yet still a new version was sent.

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 get changes made. I'm now of the opinion that I really
can't be bothered to review these patches, precisely because feedback
is clearly not welcome or if welcome, apparently acted upon.

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