RE: [PATCH net-next v5] r8169: add support for rtl8168h(revid 0x2a) + rtl8211fs fiber application

[Hau <hau@realtek.com>]

> 
> On 12.12.2022 15:11, Hau wrote:
> >> On 09.12.2022 16:29, Hau wrote:
> >>>>
> >>>> OK, I think I get a better idea of your setup.
> >>>> So it seems RTL8211FS indeed acts as media converter. Link status
> >>>> on MDI side of RTL8211FS reflects link status on fiber/serdes side.
> >>>> RTL8168H PHY has no idea whether it's connected to RJ45 magnetics
> >>>> or to the MDI side of a RTL8211FS.
> >>>>
> >>>> I think for configuring RTL8211FS you have two options:
> >>>> 1. Extend the Realtek PHY driver to support RTL8211FS fiber mode 2.
> >>>> Configure RTL8211FS from userspace (phytool, mii-tool, ..). However
> >>>> to be able to do this you may need to add a dummy netdevice
> >>>>    that RTL8211FS is attached to. When going with this option it
> >>>> may be better to avoid phylib taking control of RTL8211FS.
> >>>>    This can be done by setting the phy_mask of the bit-banged mii_bus.
> >>>
> >>> Thanks for your advaice.
> >>> Is that possible for us to register a PHY fixup
> >>> function(phy_register_fixup())
> >> to setup rtl8211fs instead of setup it in PHY driver?
> >>>
> >> From where would you like to register the PHY fixup? r8169 would be
> >> the wrong place here.
> >> There are very few drivers using a PHY fixup and AFAICS typically PHY
> >> drivers apply fixups from the config_init callback.
> >> Having said that, if possible I'd recommend to avoid using a PHY fixup.
> >>
> > Thanks for your prompt reply. I think in next patch I will remove the
> rtl8211fs phy parameter setting.
> > And only keep non speed down patch.
> > If there's any possibility I'd like to avoid the non speed down patch.
> You would have to think also about the case that a user uses ethtool to
> restrict advertisement to 100Mbps, what would break the connection.
> r8169 isn't the right place for a workaround for a broken media converter.
> The media converter should be fully transparent to r8169.
> 
> RTL8211FS should align the advertisement on MDI side with the link speed on
> fiber side, based on SGMII in-band information.
> If the fiber link is 1Gbps it must not advertise 100Mbps on MDI side.
> 
The fw in rtl8211fs will default advertise 100Mbps and 1000Mbps  on MDI side. 
We are trying to find a way to fix this issue. If we cannot fix this issue by fw than we
will submit a patch for this issue.
  
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