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.stone@xxxxxxxxxx> >>> --- >>> 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. -- ciao, al ----------------------------------- Al Stone Software Engineer Red Hat, Inc. ahs3@xxxxxxxxxx ----------------------------------- -- 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
