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-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
*/
/*******************************************************************************