Re: [dpdk-dev] [PATCH] Revert "app/testpmd: set fixed flag for exact link speed"

[Thomas Monjalon <thomas@monjalon.net>]

02/05/2019 22:27, Thomas Monjalon:
> 02/05/2019 20:31, Ferruh Yigit:
> > On 4/29/2019 10:52 AM, Thomas Monjalon wrote:
> > > 25/04/2019 17:27, Ferruh Yigit:
> > >> On 4/25/2019 2:29 PM, Thomas Monjalon wrote:
> > >>> 25/04/2019 13:47, Ferruh Yigit:
> > >>>> On 4/25/2019 9:19 AM, Thomas Monjalon wrote:
> > >>>>> 25/04/2019 00:03, Ferruh Yigit:
> > >>>>>> This reverts commit bdca79053b6aea504d02691d9319fa976062457f.
> > >>>>>>
> > >>>>>> Not all PMDs support the fixed link speed set, and link speed can be set
> > >>>>>> even with auto negotiation enabled. Reverting the patch to not break
> > >>>>>> existing usage.
> > >>>>>
> > >>>>> Which PMDs do not support this flag?
> > >>>>> Why not fixing the PMDs?
> > >>>>>
> > >>>>
> > >>>> At least ixgbe and i40e is not supporting setting a fixed speed.
> > >>>> But I am not sure if this is something to fix, the command in testpmd is to set
> > >>>> the link speed, what is the problem with setting the link speed without
> > >>>> disabling the auto-negotiation?
> > >>>
> > >>> It means it will negotiate with only one speed proposed.
> > >>
> > >> Yes.
> > >>
> > >>> The real issue is to not support the fixed flag.
> > >>
> > >> I don't know if this is a real issue but
> > >> even it is, is it an issue in the scope of this testpmd command?
> > >>
> > >> right now we are first updating the command to set fixed speed flag, and
> > >> requesting PMDs to fix for it, I am suggesting not to update the command at all.
> > > 
> > > I understand. But this change shows a broken behaviour.
> > > This is the intent of testpmd to show what works or not in PMDs.
> > > How hard is it to fix the PMDs in your opinion?
> > > 
> > 
> > As far as I can see the the fixed link speed set is not supported in the PMD.
> > 
> > It may be easy to add perhaps, I don't know, but is it really a "broken
> > behavior" to not have this support?
> > What defines that setting speed has to be "fixed speed", if this demand is not
> > there, should testpmd enforce it?
> 
> I think a PMD should support both: fixed or not.
> 
> > In mail thread we have talked that this testpmd command can get an extra
> > argument to define the speed fixed or not, this can be used to test fixed speed
> > by who wants to test/use fixed speed.
> > 
> > I am for reverting this for the release, and adding a new version next release
> > with fixed speed argument, otherwise testpmd won't be used to set the speed for
> > some PMDs.
> 
> OK

We could have an option in testpmd to test ETH_LINK_SPEED_FIXED.

Revert applied.