Re: [dpdk-dev] [PATCH v2] net/mlx5: fix link state update

[Raslan Darawsheh <rasland@nvidia.com>]

Hi,
> -----Original Message-----
> From: Ferruh Yigit <ferruh.yigit@intel.com>
> Sent: Friday, November 20, 2020 4:21 PM
> To: NBU-Contact-Thomas Monjalon <thomas@monjalon.net>
> Cc: Raslan Darawsheh <rasland@nvidia.com>; Matan Azrad
> <matan@nvidia.com>; Slava Ovsiienko <viacheslavo@nvidia.com>; Benoît
> Ganne <bganne@cisco.com>; dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH v2] net/mlx5: fix link state update
> 
> On 11/20/2020 1:50 PM, Thomas Monjalon wrote:
> > 20/11/2020 11:51, Ferruh Yigit:
> >> On 11/19/2020 6:42 PM, Thomas Monjalon wrote:
> >>> 19/11/2020 18:48, Ferruh Yigit:
> >>>> On 11/19/2020 2:20 PM, Raslan Darawsheh wrote:
> >>>>> From: Benoît Ganne <bganne@cisco.com>
> >>>>>
> >>>>> mlx5 PMD refuses to update link state if link speed is defined but
> >>>>> status is down or if link speed is undefined but status is up, even if
> >>>>> the ioctl() succeeded.
> >>>>> This prevents application to detect link up/down event, especially
> when
> >>>>> the link speed is not correctly detected.
> >>>>> As link speed is nice to have whereas link status is mandatory for
> >>>>> operations, always update link state regardless of link speed. The
> >>>>> application can then check link speed if needs be.
> >>>>>
> >>>>
> >>>> Hi Raslan, Matan,
> >>>>
> >>>> Can you please provide the Fixes tag? Also should this fix backported?
> >>>
> >>> I think it should not be backported because it is a behaviour change
> >>> relying on API doc change.
> >>>
> >>
> >> As far as I understand, API change you mention is making
> 'ETH_SPEED_NUM_UNKNOWN'
> >> speed value a valid value return value.
> >>
> >> Commit log doesn't give the context that it relies on an ethdev behavior
> change,
> >> it sounds like it is fixing behavior in the driver, it is not possible to figure
> >> out the relation without digging the mail list discussions.
> >> It would be nice to update the commit log to give more details, I think
> problem
> >> is clear but can good to add why the check was there at first place and
> why it
> >> can be removed now, etc..
> >
> > Yes I can help improving the explanations.
> >
> >> Btw with LTS, with the faulty kernel driver, PMD still won't able to get link
> >> speed which will prevent returning link status.
> >
> > With this PMD change, the link status is returned even if link speed
> > is not available.
> >
> 
> That is why I am asking if this patch should be backported :)
> 
> >> Or is the kernel driver fixed and no need to worry about this anymore?
> >
> > Yes the kernel driver is fixed since a long time.
> >
> >
> >
Thanks for your comments and reviews, 
I'll send a v3 changing the commit log accordingly.

Kindest regards,
Raslan Darawsheh