[Linuxptp-devel] expected filters listed in ethtool -T

[Keller, Jacob E]

Hi,

I am wondering what the expected filters listed in the ethtool -T ioctl
are supposed to be? Precisely, what if we support FILTER_ALL. This means
(by definition) that we support any filter since we can support it as
upscaled to FILTER_ALL

Should a driver report that it supports any particular filter if it will
upscale to a more generic filter that timestamps more packets?

Or should it only list the actual filters it upscales to and not the
more restrictive filters that will still work in the hwtstamp ioctl but
will end up reporting a more general filter?

There are some drivers I have seen do either way, and I think some
clarification on this would be quite useful.

Regards,
Jake

[Richard Cochran]

Post by Keller, Jacob E
Or should it only list the actual filters it upscales to and not the
more restrictive filters that will still work in the hwtstamp ioctl but
will end up reporting a more general filter?

This variant is the most useful one, IMHO. The ioctl should tell us
what the HW can do.

Post by Keller, Jacob E
There are some drivers I have seen do either way, and I think some
clarification on this would be quite useful.

I still think the multitude of filters is just noise and not
practical. From the user's point of view only V2_L2_EVENT,
V2_L4_EVENT, V2_EVENT, or ALL make any sense.

Thanks,
Richard

[Keller, Jacob E]

Hi,

Post by Richard Cochran

Post by Keller, Jacob E
Or should it only list the actual filters it upscales to and not the
more restrictive filters that will still work in the hwtstamp ioctl but
will end up reporting a more general filter?

This variant is the most useful one, IMHO. The ioctl should tell us
what the HW can do.

Ok this is what I've tended towards.

Post by Richard Cochran

Post by Keller, Jacob E
There are some drivers I have seen do either way, and I think some
clarification on this would be quite useful.

I still think the multitude of filters is just noise and not
practical. From the user's point of view only V2_L2_EVENT,
V2_L4_EVENT, V2_EVENT, or ALL make any sense.

Alright. So only report the most general configuration in ethtool.

I'll see about what other drivers do and posting a patch to bring
everyone in line with this for consistency.

Thanks for the input.

Post by Richard Cochran
Thanks,
Richard

Regards,
Jake