* Re: [PATCH RFC 1/5] kconfig: implement weak reverse-dependencies
[not found] ` <514AE9A3.5090209@openvz.org>
@ 2013-03-21 11:43 ` Richard Cochran
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From: Richard Cochran @ 2013-03-21 11:43 UTC (permalink / raw)
To: Konstantin Khlebnikov
Cc: Michal Marek, Andrew Morton, linux-kernel, linux-kbuild,
Tejun Heo, Greg Kroah-Hartman, netdev
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
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