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

[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..

Btw with LTS, with the faulty kernel driver, PMD still won't able to get link 
speed which will prevent returning link status.
Or is the kernel driver fixed and no need to worry about this anymore?