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Commit d1825579 authored by Bob Moore's avatar Bob Moore Committed by Rafael J. Wysocki
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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: default avatarValdis Kletnieks <valdis.kletnieks@vt.edu>
Reported-by: default avatarSabrina Dubroka <sd@queasysnail.net>
Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
Signed-off-by: default avatarLv Zheng <lv.zheng@intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 21bd7e61

drivers/acpi/acpica/acobject.h

+2 −1
Original line number Diff line number Diff line
@@ -193,7 +193,8 @@ struct acpi_object_method { 
#define ACPI_METHOD_INTERNAL_ONLY       0x02	/* Method is implemented internally (_OSI) */

#define ACPI_METHOD_SERIALIZED          0x04	/* Method is serialized */

#define ACPI_METHOD_SERIALIZED_PENDING  0x08	/* Method is to be marked serialized */

#define ACPI_METHOD_MODIFIED_NAMESPACE  0x10	/* Method modified the namespace */

#define ACPI_METHOD_IGNORE_SYNC_LEVEL   0x10	/* Method was auto-serialized at table load time */

#define ACPI_METHOD_MODIFIED_NAMESPACE  0x20	/* Method modified the namespace */



/******************************************************************************

 *

drivers/acpi/acpica/dsmethod.c

+19 −5
Original line number Diff line number Diff line
@@ -175,8 +175,15 @@ acpi_ds_detect_named_opcodes(struct acpi_walk_state *walk_state, 
	 * 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",
@@ -349,12 +356,18 @@ acpi_ds_begin_method_execution(struct acpi_namespace_node *method_node, 
		/*

		 * 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.

		       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)",
@@ -800,7 +813,8 @@ acpi_ds_terminate_control_method(union acpi_operand_object *method_desc, 
			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;

		}