Re: [PATCH RFC 1/5] kconfig: implement weak reverse-dependencies

On Thu, Mar 21, 2013 at 03:06:11PM +0400, Konstantin Khlebnikov wrote:

As I see this technology requires special dedicated server in the local
network, thus it's unusable in most situations. But it starts working
without any actions from the user (please fix me if I'm wrong).

Perhaps you don't have a very clear picture of how this PTP stuff
works. Even when the PHC and time stamping code is compiled in, it
does *not* start working unless the end user turns it on, via the
SIOCSHWTSTAMP and SO_TIMESTAMPING options.

See: Documentation/networking/timestamping.txt
     Documentation/ptp/ptp.txt
 

Thus this code enables some rarely used parts of hardware.
After seeing several weird bugs in ethernet devices I prefer to
keep unused/unwanted features off.

Just compiling drivers into kernel does not really change the behavior
of the hardware. The only drawback I know of is that it adds (minimal)
overhead into the packet processing paths, but that is a software
issue.

I don't mean to start a big discussion here. The question of whether
to have PHC support a compile time option should be discussed on the
netdev list (added on CC just in case).

Thanks,
Richard