Hi Al, On Fri, Jun 19, 2015 at 12:36 AM, Al Stone <al.stone@xxxxxxxxxx> wrote: > Add the ACPI_SPEC_VERSION() macro to build a proper version number from > a major and minor revision number. Add also the ACPI_FADT_SPEC_VERSION > that constructs a proper version number from the entries in the current > FADT. > > These macros are added in order to simplify retrieving and comparing ACPI > specification version numbers, since this is becoming a more frequent need. > In particular, there are some architectures that require at least a certain > version of the spec, and there are differences in some structure sizes that > have changed with recent versions but can only be tracked by spec version > number. > > Signed-off-by: Al Stone <al.stone@xxxxxxxxxx> > --- > include/linux/acpi.h | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/include/linux/acpi.h b/include/linux/acpi.h > index a4acb55..33ed313 100644 > --- a/include/linux/acpi.h > +++ b/include/linux/acpi.h > @@ -48,6 +48,11 @@ > #include <acpi/acpi_io.h> > #include <asm/acpi.h> > > +#define ACPI_SPEC_VERSION(major, minor) ((major<<8)|minor) One nit here. acpi_gbl_FADT.header.revision is of type u8 originally, so shifting it by 8 bit positions only works due to some implicit type casting I suppose. Moreover, it is not entirely clear why the macro is specific to the computation of the ACPI spec version. So I'd drop ACPI_SPEC_VERSION and only define ACPI_FADT_SPEC_VERSION as something like #define ACPI_FADT_SPEC_VERSION (((unsigned int)acpi_gbl_FADT.header.revision << 8) | (unsigned int)acpi_gbl_FADT.minor_revision) Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
