ACPICA: Ignore sync_level for methods that have been auto-serialized.
Cannot use a sync_level for methods that have been serialized at load-time
or runtime because this may interfere with any existing use of sync_levels
within the ASL code. So, we simply ignore the sync_level for these methods,
thus preserving any existing sync_level priorities. Note, the use of
sync_levels is actually rather rare within BIOS ASL code.
References: http://www.spinics.net/lists/linux-acpi/msg49496.html
Reported-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Reported-by: Sabrina Dubroka <sd@queasysnail.net>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/acpi/acpica/dsmethod.c b/drivers/acpi/acpica/dsmethod.c
index 73764c7..3c7f737 100644
--- a/drivers/acpi/acpica/dsmethod.c
+++ b/drivers/acpi/acpica/dsmethod.c
@@ -175,8 +175,15 @@
* At this point, we know we have a Named object opcode.
* Mark the method as serialized. Later code will create a mutex for
* this method to enforce serialization.
+ *
+ * Note, ACPI_METHOD_IGNORE_SYNC_LEVEL flag means that we will ignore the
+ * Sync Level mechanism for this method, even though it is now serialized.
+ * Otherwise, there can be conflicts with existing ASL code that actually
+ * uses sync levels.
*/
- walk_state->method_desc->method.info_flags |= ACPI_METHOD_SERIALIZED;
+ walk_state->method_desc->method.sync_level = 0;
+ walk_state->method_desc->method.info_flags |=
+ (ACPI_METHOD_SERIALIZED | ACPI_METHOD_IGNORE_SYNC_LEVEL);
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Method serialized [%4.4s] %p - [%s] (%4.4X)\n",
@@ -349,13 +356,19 @@
/*
* The current_sync_level (per-thread) must be less than or equal to
* the sync level of the method. This mechanism provides some
- * deadlock prevention
+ * deadlock prevention.
+ *
+ * If the method was auto-serialized, we just ignore the sync level
+ * mechanism, because auto-serialization of methods can interfere
+ * with ASL code that actually uses sync levels.
*
* Top-level method invocation has no walk state at this point
*/
if (walk_state &&
- (walk_state->thread->current_sync_level >
- obj_desc->method.mutex->mutex.sync_level)) {
+ (!(obj_desc->method.
+ info_flags & ACPI_METHOD_IGNORE_SYNC_LEVEL))
+ && (walk_state->thread->current_sync_level >
+ obj_desc->method.mutex->mutex.sync_level)) {
ACPI_ERROR((AE_INFO,
"Cannot acquire Mutex for method [%4.4s], current SyncLevel is too large (%u)",
acpi_ut_get_node_name(method_node),
@@ -800,7 +813,8 @@
method_desc->method.info_flags &=
~ACPI_METHOD_SERIALIZED_PENDING;
method_desc->method.info_flags |=
- ACPI_METHOD_SERIALIZED;
+ (ACPI_METHOD_SERIALIZED |
+ ACPI_METHOD_IGNORE_SYNC_LEVEL);
method_desc->method.sync_level = 0;
}