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authorMarcelo Tosatti <mtosatti@redhat.com>2012-10-29 19:15:32 -0200
committerMarcelo Tosatti <mtosatti@redhat.com>2012-10-29 19:15:32 -0200
commit19bf7f8ac3f8131100027281c495dbbe00cd5ae0 (patch)
tree270b97e3ca47c0f62a1babca2ae37f79a76a309c /include/acpi/actbl3.h
parent787c57c0fb393fe8a3974d300ddcfe30373386fe (diff)
parent35fd3dc58da675d659513384221349ef90749a01 (diff)
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Merge remote-tracking branch 'master' into queue
Merge reason: development work has dependency on kvm patches merged upstream. Conflicts: arch/powerpc/include/asm/Kbuild arch/powerpc/include/asm/kvm_para.h Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'include/acpi/actbl3.h')
-rw-r--r--include/acpi/actbl3.h13
1 files changed, 9 insertions, 4 deletions
diff --git a/include/acpi/actbl3.h b/include/acpi/actbl3.h
index f65a0ed869eb..8c61b5fe42a4 100644
--- a/include/acpi/actbl3.h
+++ b/include/acpi/actbl3.h
@@ -75,7 +75,6 @@
/* Reserved table signatures */
#define ACPI_SIG_CSRT "CSRT" /* Core System Resources Table */
-#define ACPI_SIG_DBG2 "DBG2" /* Debug Port table 2 */
#define ACPI_SIG_MATR "MATR" /* Memory Address Translation Table */
#define ACPI_SIG_MSDM "MSDM" /* Microsoft Data Management Table */
#define ACPI_SIG_WPBT "WPBT" /* Windows Platform Binary Table */
@@ -87,9 +86,15 @@
#pragma pack(1)
/*
- * Note about bitfields: The u8 type is used for bitfields in ACPI tables.
- * This is the only type that is even remotely portable. Anything else is not
- * portable, so do not use any other bitfield types.
+ * Note: C bitfields are not used for this reason:
+ *
+ * "Bitfields are great and easy to read, but unfortunately the C language
+ * does not specify the layout of bitfields in memory, which means they are
+ * essentially useless for dealing with packed data in on-disk formats or
+ * binary wire protocols." (Or ACPI tables and buffers.) "If you ask me,
+ * this decision was a design error in C. Ritchie could have picked an order
+ * and stuck with it." Norman Ramsey.
+ * See http://stackoverflow.com/a/1053662/41661
*/
/*******************************************************************************