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

[Thomas Monjalon]

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 at 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.

> Or is the kernel driver fixed and no need to worry about this anymore?

Yes the kernel driver is fixed since a long time.