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-rw-r--r--include/acpi/actbl1.h16
1 files changed, 12 insertions, 4 deletions
diff --git a/include/acpi/actbl1.h b/include/acpi/actbl1.h
index 300d14e..280fc45 100644
--- a/include/acpi/actbl1.h
+++ b/include/acpi/actbl1.h
@@ -79,9 +79,15 @@
#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
*/
/*******************************************************************************
@@ -489,7 +495,9 @@ enum acpi_hest_notify_types {
ACPI_HEST_NOTIFY_LOCAL = 2,
ACPI_HEST_NOTIFY_SCI = 3,
ACPI_HEST_NOTIFY_NMI = 4,
- ACPI_HEST_NOTIFY_RESERVED = 5 /* 5 and greater are reserved */
+ ACPI_HEST_NOTIFY_CMCI = 5, /* ACPI 5.0 */
+ ACPI_HEST_NOTIFY_MCE = 6, /* ACPI 5.0 */
+ ACPI_HEST_NOTIFY_RESERVED = 7 /* 7 and greater are reserved */
};
/* Values for config_write_enable bitfield above */