Warnings from silentoldconfig (Re: [GIT PULL] PCI updates for v3.11)

[Michal Marek <mmarek@suse.cz>]

On Fri, Aug 02, 2013 at 01:28:25PM -0700, Linus Torvalds wrote:
> On Fri, Aug 2, 2013 at 11:17 AM, Bjorn Helgaas <bhelgaas@google.com> wrote:
> >
> > Yinghai is still working on another SR-IOV-related fix or two, which
> > will be simpler if pciehp is non-modular, so I included the Kconfig
> > changes now to get them in earlier.
> 
> Hmm. Doing a trivial "make allmoconfig" for testing, I get
> 
>   include/config/auto.conf:3014:warning: symbol value 'm' invalid for
> HOTPLUG_PCI_PCIE
>   include/config/auto.conf:4711:warning: symbol value 'm' invalid for
> HOTPLUG_PCI
> 
> but that may be a build system issue with stale data from the
> *previous* "make allmodconfig". Regardless, that makes me worried.
> 
> Adding Michal Marek to the discussion. I'm currently doing a new "make
> allmodconfig" after having done a "git clean -dqfx" to see if the
> error remains. If it does, I will unpull. If it is gone, I'm going to
> assume the Kconfig changes are ok, but that our build system is
> missing some dependency.

Added Yann and the linux-kbuild list to CC. Reproducer:

  git checkout 1fe0135
  make mrproper
  make allmodconfig
  make silentoldconfig
  git checkout aa8032b
  make allmodconfig
  make silentoldconfig

conf_write_autoconf() first calls conf_split_config() to generate the
include/config/**.h hierarchy, then generates include/config/auto.conf.
For some reason, conf_split_config() reads include/config/auto.conf,
which may not exist yet or may be out of date. Yann, can anything break
if we simply do not read that file from conf_split_config(), like this?

diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index c55c227..8c90835 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -829,16 +829,12 @@ next:
 
 static int conf_split_config(void)
 {
-	const char *name;
 	char path[PATH_MAX+1];
 	char *s, *d, c;
 	struct symbol *sym;
 	struct stat sb;
 	int res, i, fd;
 
-	name = conf_get_autoconfig_name();
-	conf_read_simple(name, S_DEF_AUTO);
-
 	if (chdir("include/config"))
 		return 1;
 
Thanks,
Michal