As I said its a detail but details are always important
I repeat: I have done serveral kernel upgrade during the last months, never did make oldconfig, and never lost my old configuration.
If you do directly make (x,menu,)config, this rule is applied:
Code:
# If .config is newer than include/linux/autoconf.h, someone tinkered
# with it and forgot to run make oldconfig.
# If kconfig.d is missing then we are probarly in a cleaned tree so
# we execute the config step to be sure to catch updated Kconfig files
include/linux/autoconf.h: .kconfig.d .config
$(Q)mkdir -p include/linux
$(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig
And you end up with a normal screen (as if you were compiling your first kernel) but with your old settings. For sure you have to check all options and verify if they are coherent, and you can see the new features they are labelled with (NEW)
As I said, its easier (even more for new linux users) to just copy an old .config and then run make xconfig. Doing make oldconfig doesn't harm but to my mind its not necessary anymore, it just adds complexity.
