From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 25 Apr 2013 14:30:45 +0800 From: Feng Tang To: John Stultz Cc: lkml , stable , Kay Sievers , Jason Gunthorpe , Thomas Gleixner Subject: Re: [PATCH] time: Revert ALWAYS_USE_PERSISTENT_CLOCK compile time optimizaitons Message-ID: <20130425063045.GA2597@feng-snb> References: <1366828376-18124-1-git-send-email-john.stultz@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1366828376-18124-1-git-send-email-john.stultz@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: On Wed, Apr 24, 2013 at 11:32:56AM -0700, John Stultz wrote: > Kay Sievers noted that the ALWAYS_USE_PERSISTENT_CLOCK config, > which enables some minor compile time optimization to avoid > uncessary code in mostly the suspend/resume path could cause > problems for userland. > > In particular, the dependency for RTC_HCTOSYS on > !ALWAYS_USE_PERSISTENT_CLOCK, which avoids setting the time > twice and simplifies suspend/resume, has the side effect > of causing the /sys/class/rtc/rtcN/hctosys flag to always be > zero, and this flag is commonly used by udev to setup the > /dev/rtc symlink to /dev/rtcN, which can cause pain for > older applications. > > While the udev rules could use some work to be less fragile, > breaking userland should strongly be avoided. Additionally > the compile time optimizations are fairly minor, and the code > being optimized is likely to be reworked in the future, so > lets revert this change. > > I suspect this will miss 3.9-final, so marking it for 3.9-stable. thanks Acked-by: Feng Tang