When a symbol changes type from tristate to bool, and was previously set to
'm', a subsequent silentoldconfig would warn about inconsistency, such as:
include/config/auto.conf:3014:warning: symbol value 'm' invalid for
HOTPLUG_PCI_PCIE
Seen by Linus with the merge in aa8032b (sequence to reproduce by Michal):
git checkout 1fe0135
make mrproper
make allmodconfig
make silentoldconfig
git checkout aa8032b
make allmodconfig
make silentoldconfig
Since HOTPLUG_PCI_PCIE changed from tristate to bool in aa8032b, it was
previously set to 'm' in auto.conf by the first allmodconfig+silentoldconfig,
but then was set to 'y' by the second allmodconfig. Then the second
silentoldconfig prints the warning.
The warning in this case is a spurious warning, which happens at the time
kconfig tries to detect symbols that have changed, to touch the empty
header files in include/config used for dependency-tracking by make.
Silence the warning when we read the old auto.conf file, since it is
perfectly legit that a symbol changed type since the previous call.
Thread in:
http://marc.info/?l=linux-pci&m=137569198904000&w=2
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
04b19b773a