Re: [PATCH net-next 5/8] ice: register 1588 PTP clock device object for E810 devices

On Mon, 14 Jun 2021 13:51:57 -0700 Jacob Keller wrote:

quoted

Ah, you're right, ptp4l will explicitly cap the freq adjustments
based on max_adj from sysfs, so setting max_adj too low could impact
the convergence time in strange scenarios.

Your patch to fix it so that the conversion from scaled_ppm to ppb can't
overflow is the correct approach, here. The scaled_ppm function didn't
account for the fact that the provided adjustment could overflow the s32.

Increasing that to s64 ensures it won't overflow and prevents invalid
bogus frequencies from passing that check.

On second though I went with long for ppb IOW the same as scaled_ppm,
presumably the problem does not exist on 32bit, so no point using 64b
everywhere.