RE: [PATCH] net/ixgbe: Treat 1G Cu SFPs as 1G SX on the X550 devices

["Zhang, Qi Z" <qi.z.zhang@intel.com>]

> -----Original Message-----
> From: Jeff Daly <jeffd@silicom-usa.com>
> Sent: Saturday, May 21, 2022 2:03 AM
> To: Zhang, Qi Z <qi.z.zhang@intel.com>; Thomas Monjalon
> <thomas@monjalon.net>; dev@dpdk.org
> Cc: Stephen Douthit <stephend@silicom-usa.com>; Yang, Qiming
> <qiming.yang@intel.com>; Wu, Wenjun1 <wenjun1.wu@intel.com>
> Subject: RE: [PATCH] net/ixgbe: Treat 1G Cu SFPs as 1G SX on the X550 devices
> 
> 
> 
> > -----Original Message-----
> > From: Zhang, Qi Z <qi.z.zhang@intel.com>
> > Sent: Thursday, May 19, 2022 8:15 PM
> > To: Thomas Monjalon <thomas@monjalon.net>; dev@dpdk.org
> > Cc: Stephen Douthit <stephend@silicom-usa.com>; Jeff Daly
> > <jeffd@silicom- usa.com>; Yang, Qiming <qiming.yang@intel.com>; Wu,
> > Wenjun1 <wenjun1.wu@intel.com>
> > Subject: RE: [PATCH] net/ixgbe: Treat 1G Cu SFPs as 1G SX on the X550
> > devices
> >
> > Caution: This is an external email. Please take care when clicking
> > links or opening attachments.
> >
> >
> > > -----Original Message-----
> > > From: Thomas Monjalon <thomas@monjalon.net>
> > > Sent: Wednesday, April 13, 2022 10:21 PM
> > > To: dev@dpdk.org
> > > Cc: Stephen Douthit <stephend@silicom-usa.com>; Jeff Daly
> > > <jeffd@silicom- usa.com>; Wang, Haiyue <haiyue.wang@intel.com>;
> > > Yang, Qiming <qiming.yang@intel.com>; Wu, Wenjun1
> > > <wenjun1.wu@intel.com>
> > > Subject: Re: [PATCH] net/ixgbe: Treat 1G Cu SFPs as 1G SX on the
> > > X550 devices
> > >
> > > Please, could we have a review of this patch?
> > > +Cc new ixgbe maintainers
> > >
> > >
> > > 07/03/2022 23:34, jeffd@silicom-usa.com:
> > > > From: Stephen Douthit <stephend@silicom-usa.com>
> > > >
> > > > 1G Cu SFPs are not officially supported on the X552/X553 family of
> > > > devices but treat them as 1G SX modules since they usually work.
> > > > Print a warning though since support isn't validated, similar to
> > > > what already happens for other unofficially supported SFPs enabled
> > > > via the allow_unsupported_sfps parameter inherited from the
> > > > mainline
> > Linux driver.
> > > >
> > > > Signed-off-by: Stephen Douthit <stephend@silicom-usa.com>
> > > > Signed-off-by: Jeff Daly <jeffd@silicom-usa.com>
> >
> > I think we need a devargs for this feature with well documentation So,
> > it should not break existing behavior by default, but allow people to
> > take risk if they know what they are doing.
> >
> 
> there was already a patch submitted to IWL mailing list for this feature in the
> base driver, which was rejected.
> https://patchwork.ozlabs.org/project/intel-wired-
> lan/patch/20220414201329.27714-1-jeffd@silicom-usa.com/

OK, thanks for sharing this, 

But base on the concern of the previous comment 

" As for 1G Cu SFP treating it as 1G SX, some 1G-Base-T SFP modules require the use
of RX_ILOS and some Intel Ethernet products don't support that."

We may have a risk to accept the code as default behavior

But devargs is allowed in DPDK for device-specific features.


> 
> > Thanks
> > Qi
> >
> >
> > > > ---
> > > >  drivers/net/ixgbe/base/ixgbe_x550.c | 14 +++++++++++++-
> > > >  1 file changed, 13 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/drivers/net/ixgbe/base/ixgbe_x550.c
> > > > b/drivers/net/ixgbe/base/ixgbe_x550.c
> > > > index 8810d1658e..8d1bc6c80d 100644
> > > > --- a/drivers/net/ixgbe/base/ixgbe_x550.c
> > > > +++ b/drivers/net/ixgbe/base/ixgbe_x550.c
> > > > @@ -1538,9 +1538,21 @@ STATIC s32
> > > ixgbe_supported_sfp_modules_X550em(struct ixgbe_hw *hw, bool
> > > *linear)
> > > >     case ixgbe_sfp_type_1g_lha_core1:
> > > >             *linear = false;
> > > >             break;
> > > > -   case ixgbe_sfp_type_unknown:
> > > > +   /* Copper SFPs are not officially supported for x550em
> > > > + devices, but
> > can
> > > > +    * often be made to work at fixed 1G speeds.  Pretend they're 1g_sx
> > > > +    * modules here to allow g.Fast DSL SFPs to work.
> > > > +    */
> > > >     case ixgbe_sfp_type_1g_cu_core0:
> > > > +           EWARN(hw, "Pretending that unsupported 1g_cu SFP is
> > > 1g_sx\n");
> > > > +           *linear = false;
> > > > +           hw->phy.sfp_type = ixgbe_sfp_type_1g_sx_core0;
> > > > +           break;
> > > >     case ixgbe_sfp_type_1g_cu_core1:
> > > > +           EWARN(hw, "Pretending that unsupported 1g_cu SFP is
> > > 1g_sx\n");
> > > > +           *linear = false;
> > > > +           hw->phy.sfp_type = ixgbe_sfp_type_1g_sx_core1;
> > > > +           break;
> > > > +   case ixgbe_sfp_type_unknown:
> > > >     default:
> > > >             return IXGBE_ERR_SFP_NOT_SUPPORTED;
> > > >     }
> > >
> > >
> > >
> > >
> > >