Re: [PATCH net] Revert "net/mlx5: Update cyclecounter shift value to improve ptp free running mode precision"

[Rahul Rameshbabu <rrameshbabu@nvidia.com>]

On Mon, 21 Aug, 2023 21:37:51 +0000 Vadim Fedorenko <vadfed@meta.com> wrote:
> Hi!
>
> I have tested the diff, looks like it works on both CX4 and CX6 cards I have
> right now. Wasn't able to find CX5 to test it, but I think it's ok to publish it
> and wait for some other users of CX5 to test.

Thanks Vadim. I have tested on CX5 myself, but a CX5 user reached out to
me directly since he was also impacted by the original change. If we
can, getting his feedback would be good.

>
> Best,
> Vadim
>
> ________________________________________
> From: Saeed Mahameed <saeed@kernel.org>
> Sent: 17 August 2023 17:37
> To: Jakub Kicinski
> Cc: Saeed Mahameed; Vadim Fedorenko; Rahul Rameshbabu; Gal Pressman; Bar
> Shapira; Vadim Fedorenko; Richard Cochran; netdev@vger.kernel.org
> Subject: Re: [PATCH net] Revert "net/mlx5: Update cyclecounter shift value to
> improve ptp free running mode precision"
>
> On 16 Aug 19:38, Jakub Kicinski wrote:
>>On Tue, 15 Aug 2023 08:15:07 -0700 Vadim Fedorenko wrote:
>>> From: Vadim Fedorenko <vadim.fedorenko@linux.dev>
>>>
>>> This reverts commit 6a40109275626267ebf413ceda81c64719b5c431.
>>>
>>> There was an assumption in the original commit that all the devices
>>> supported by mlx5 advertise 1GHz as an internal timer frequency.
>>> Apparently at least ConnectX-4 Lx (MCX4431N-GCAN) provides 156.250Mhz
>>> as an internal frequency and the original commit breaks PTP
>>> synchronization on these cards.
>>
>>Hi Saeed, any preference here? Given we're past -rc6 and the small
>>size of the revert it seems like a tempting solution?
>
> Rahul's solution is also very small and already passed review, we will be
> conducting some tests, share the patch with Vadim for testing and I will be
> submitting it early next week.
>

Hi Saeed, I think we can send the patch out whenever you want to. I will
share the patch directly with the individual CX5 user who reached out to
me as well.

--
Thanks,

Rahul Rameshbabu