On Friday, July 03, 2015 01:22:13 PM Al Stone wrote: > On 07/02/2015 11:23 PM, Hanjun Guo wrote: > > Hi Rafael, > > > > On 2015/7/3 8:21, Rafael J. Wysocki wrote: > >> On Thursday, July 02, 2015 05:48:34 PM Al Stone wrote: > >>> Add the __ACPI_FADT_SPEC_VERSION() helper macro to build a proper version > >>> number from a major and minor revision number. Add also macros that use > >>> the helper to construct the current version from the values in the FADT > >>> (i.e., ACPI_FADT_SPEC_VERSION) and both the 5.1 and 6.0 versions. > >>> > >>> 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. > >>> > >>> Fixes: aeb823bbacc2 (ACPICA: ACPI 6.0: Add changes for FADT table.) > >>> Signed-off-by: Al Stone <al.st...@linaro.org> > >>> --- > >>> include/linux/acpi.h | 10 ++++++++++ > >>> 1 file changed, 10 insertions(+) > >>> > >>> diff --git a/include/linux/acpi.h b/include/linux/acpi.h > >>> index c471dfc..0e525e8 100644 > >>> --- a/include/linux/acpi.h > >>> +++ b/include/linux/acpi.h > >>> @@ -48,6 +48,16 @@ > >>> #include <acpi/acpi_io.h> > >>> #include <asm/acpi.h> > >>> > >>> +#define __ACPI_FADT_SPEC_VERSION(major, minor) \ > >>> + ((unsigned int)major << 8 | (unsigned int)minor) > >>> + > >>> +#define ACPI_FADT_SPEC_VERSION \ > >>> + __ACPI_FADT_SPEC_VERSION(acpi_gbl_FADT.header.revision, \ > >>> + acpi_gbl_FADT.minor_revision) > >>> + > >>> +#define ACPI_FADT_SPEC_VERSION_51 __ACPI_FADT_SPEC_VERSION(5, 1) > >>> +#define ACPI_FADT_SPEC_VERSION_60 __ACPI_FADT_SPEC_VERSION(6, 0) > >> I'd add underscores here, eg. ACPI_FADT_SPEC_VERSION_6_0 > > > > Agreed. > > Will do. This was a flip of the coin, on my part. > > >> And what if there is 5.2 or even 5.3? > > > > Hmm, do you mean in the future or just now? for both two cases, > > only 5.1 and 5.1 errata (still has the same ACPI version with 5.1) > > will be available, then jump to 6.0 and going forward if new versions > > in the future. > > > > I'm not sure if I understand your question correctly, if > > not, please correct me :) > > > > Thanks > > Hanjun > > I'm not sure I understand the question, either. Traditionally, the > spec versioning has been exclusively linear -- i.e., now that 6.0 > has replaced 5.1, there will be no more 5.x. There may be errata > published (e.g., there was a 5.1A, and a 6.0A is forthcoming) but > the errata are not encoded in tables anywhere since they are meant > only as corrections to the base version. This is unlikely to change, > but not impossible, of course :). > > The only reason for putting in macros for 5.1 and 6.0 is that those > are the versions that I'm concerned with for this particular fix and > I know I will use them. If others are needed, I'd have those that > need them add them.
It seems to me that you only need to compare acpi_gbl_FADT.header.revision with 6 for this fix, though (if less than 6, use the old way, or use the new way otherwise). Isn't that the case? Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
