From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ea0-f178.google.com ([209.85.215.178]:60487 "EHLO mail-ea0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932344Ab3CULnP (ORCPT ); Thu, 21 Mar 2013 07:43:15 -0400 Date: Thu, 21 Mar 2013 12:43:08 +0100 From: Richard Cochran Subject: Re: [PATCH RFC 1/5] kconfig: implement weak reverse-dependencies Message-ID: <20130321114307.GA6716@netboy.at.omicron.at> References: <20130321082256.21557.68351.stgit@zurg> <20130321102200.GB2341@netboy.at.omicron.at> <514AE9A3.5090209@openvz.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <514AE9A3.5090209@openvz.org> Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: Konstantin Khlebnikov Cc: Michal Marek , Andrew Morton , linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, Tejun Heo , Greg Kroah-Hartman , netdev@vger.kernel.org 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