Merge branches 'acpica', 'acpidump', 'intel-idle', 'misc', 'module_acpi_driver-simpli...

[karo-tx-linux.git] / include / acpi / actbl3.h

diff --git a/include/acpi/actbl3.h b/include/acpi/actbl3.h
index f65a0ed869ebc327bceee545bbe7d905726b05b4..8c61b5fe42a48417fb7b9b4080fac0ff743978a4 100644 (file)
--- 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
  */
 
 /*******************************************************************************