Subject: Re: [PATCH RFC V1 net-next 3/4] net: Let the active time stamping layer be selectable.

From: Kurt Kanzenbach <[email-masked]>
Date: Fri, 21 Jan 2022 12:05:22 +0100

On Thu Jan 20 2022, Vladimir Oltean wrote:
> Hi Richard,
>
> On Mon, Jan 03, 2022 at 03:25:54PM -0800, Richard Cochran wrote:
>> Make the sysfs knob writable, and add checks in the ioctl and time
>> stamping paths to respect the currently selected time stamping layer.
>> 
>> Signed-off-by: Richard Cochran <[email-masked]>
>> ---
>
> Could we think of a more flexible solution? Your proposal would not
> allow a packet to have multiple hwtstamps, and maybe that would be
> interesting for some use cases (hardware testing, mostly).

One use case i can think of for having multiple hwtimestamps per packet
is crosstimestamping. Some devices such as hellcreek have multiple PHCs
and allow generation of such crosstimestamps.

Thanks,
Kurt