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authorBob Moore <robert.moore@intel.com>2007-02-02 19:48:18 +0300
committerLen Brown <len.brown@intel.com>2007-02-02 21:14:20 -0500
commitc81da66608d65dab04730582dfdfcdcab779e2fe (patch)
treee1d2936a457d3ac2b359b4fc676bedfd341fee86 /drivers/acpi/namespace
parent8f9337c88335846b01801b1047a4caf10527a320 (diff)
downloadblackbird-op-linux-c81da66608d65dab04730582dfdfcdcab779e2fe.tar.gz
blackbird-op-linux-c81da66608d65dab04730582dfdfcdcab779e2fe.zip
ACPICA: Delete recursive feature of ACPI Global Lock
Completed a new design and implementation for the ACPI Global Lock support. On the OS side, the global lock is now treated as a standard AML mutex. Previously, multiple OS threads could acquire the global lock simultaneously, but this could cause the BIOS to be starved by the lock in cases such as the Embedded Controller driver, where there is a tight coupling between the OS and the BIOS. Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi/namespace')
-rw-r--r--drivers/acpi/namespace/nsaccess.c36
1 files changed, 16 insertions, 20 deletions
diff --git a/drivers/acpi/namespace/nsaccess.c b/drivers/acpi/namespace/nsaccess.c
index c1c6c236df9a..b2ef6730be81 100644
--- a/drivers/acpi/namespace/nsaccess.c
+++ b/drivers/acpi/namespace/nsaccess.c
@@ -195,31 +195,27 @@ acpi_status acpi_ns_root_initialize(void)
obj_desc->mutex.sync_level =
(u8) (ACPI_TO_INTEGER(val) - 1);
- if (ACPI_STRCMP(init_val->name, "_GL_") == 0) {
-
- /* Create a counting semaphore for the global lock */
+ /* Create a mutex */
+
+ status =
+ acpi_os_create_mutex(&obj_desc->mutex.
+ os_mutex);
+ if (ACPI_FAILURE(status)) {
+ acpi_ut_remove_reference(obj_desc);
+ goto unlock_and_exit;
+ }
- status =
- acpi_os_create_semaphore
- (ACPI_NO_UNIT_LIMIT, 1,
- &acpi_gbl_global_lock_semaphore);
- if (ACPI_FAILURE(status)) {
- acpi_ut_remove_reference
- (obj_desc);
- goto unlock_and_exit;
- }
+ /* Special case for ACPI Global Lock */
- /* Mark this mutex as very special */
+ if (ACPI_STRCMP(init_val->name, "_GL_") == 0) {
+ acpi_gbl_global_lock_mutex =
+ obj_desc->mutex.os_mutex;
- obj_desc->mutex.os_mutex =
- ACPI_GLOBAL_LOCK;
- } else {
- /* Create a mutex */
+ /* Create additional counting semaphore for global lock */
status =
- acpi_os_create_mutex(&obj_desc->
- mutex.
- os_mutex);
+ acpi_os_create_semaphore(1, 1,
+ &acpi_gbl_global_lock_semaphore);
if (ACPI_FAILURE(status)) {
acpi_ut_remove_reference
(obj_desc);
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