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

[Thomas Monjalon <thomas@monjalon.net>]

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