[PATCH] smbios: Fix calculating BIOS Release Date

[Pali Rohár]

On Friday 23 April 2021 10:25:21 Bin Meng wrote:
> Hi Pali,
> 
> On Fri, Apr 23, 2021 at 12:10 AM Pali Rohár <pali at kernel.org> wrote:
> >
> > BIOS Release Date must be in format mm/dd/yyyy and must be release date.
> > U-Boot currently sets BIOS Release Date from U_BOOT_DMI_DATE macro which is
> > generated from current build timestamp.
> >
> > Fix this issue by setting U_BOOT_DMI_DATE macro to U-Boot version which is
> > better approximation of U-Boot release date than current build timestamp.
> > Current U-Boot versioning is in format yyyy.mm so as a day choose 01.
> >
> > Some operating systems are using BIOS Release Date for detecting when was
> > SMBIOS table filled or if it could support some feature (e.g. BIOS from
> > 1990 cannot support features invented in 2000). So this change also ensures
> > that recompiling U-Boot from same sources but in different year does not
> > change behavior of some operating systems.
> >
> > Macro U_BOOT_DMI_DATE is not used in other file than lib/smbios.c
> > so remove it from global autogenerated files and also from Makefile.
> >
> > Signed-off-by: Pali Rohár <pali at kernel.org>
> > ---
> >  Makefile                |  2 --
> >  doc/develop/version.rst |  1 -
> >  lib/smbios.c            | 23 +++++++++++++++++++++++
> >  3 files changed, 23 insertions(+), 3 deletions(-)
> >
> 
> With this change the U-Boot date is only the release date, so one
> cannot tell exact BIOS date on which U-Boot was built from.

Hello Bin! I understood that this is expected and it should be the
release date, not the build date. But maybe it has different meanings in
different contexts?