From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Date: Wed, 22 Oct 2014 22:51:33 +0200 Subject: [Buildroot] [PATCH] infra/pkg-kconfig: fix saving the config file In-Reply-To: <1413836616-4209-1-git-send-email-yann.morin.1998@free.fr> References: <1413836616-4209-1-git-send-email-yann.morin.1998@free.fr> Message-ID: <20141022225133.59ae7d55@free-electrons.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Dear Yann E. MORIN, On Mon, 20 Oct 2014 22:23:36 +0200, Yann E. MORIN wrote: > When saving (aka updating) the configuration file of a kconfig package, > a subsequent call to "make" would rebuild the package, even though the > configuration did not actually change. > > It took quite a while to understand why. But the reason is so simple and > obvious, when you think about it: > > - $(@D)/.config depends on the config file $(BUSYBOX_CONFIG_FILE) > - busybox-update-config then copies $(@D)/.config back to the config > file $(BUSYBOX_CONFIG_FILE) > - so the config file is newer than $(@D)/.config > > So, in the next run, pkg-kconfig believes that it has to rebuild > busybox. Bummer... :-/ > > So, the fix is very trivial, and just requires asking "cp" to preserve > timestamps, so the dependency does not kick in at the next run. > > Signed-off-by: "Yann E. MORIN" > Cc: Thomas De Schampheleire Applied, thanks. Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com