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

From: Rahul Rameshbabu <[email-masked]>
Date: Tue, 15 Aug 2023 09:53:27 -0700

On Tue, 15 Aug, 2023 08:15:07 -0700 Vadim Fedorenko <[email-masked]> wrote:
> From: Vadim Fedorenko <[email-masked]>
>
> 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.
>
> Signed-off-by: Vadim Fedorenko <[email-masked]>
> ---

I agree with this revert. This change was made with the assumption that
all mlx5 compatible devices were running a 1Ghz internal timer. Will
sync with folks internally about how we can support higher precision
free running mode while accounting for the different device timer clock
speeds.

Reviewed-by: Rahul Rameshbabu <[email-masked]>