1 files changed, 18 insertions, 14 deletions
diff --git a/sys/contrib/dev/acpica/exsystem.c b/sys/contrib/dev/acpica/exsystem.c
index ae38ec8..ba4ef4e 100644
--- a/sys/contrib/dev/acpica/exsystem.c
+++ b/sys/contrib/dev/acpica/exsystem.c
@@ -2,7 +2,7 @@
 /******************************************************************************
  *
  * Module Name: exsystem - Interface to OS services
- *              $Revision: 76 $
+ *              $Revision: 79 $
  *
  *****************************************************************************/
 
@@ -188,11 +188,16 @@ AcpiExSystemWaitSemaphore (
  *
  * FUNCTION:    AcpiExSystemDoStall
  *
- * PARAMETERS:  HowLong             - The amount of time to stall
+ * PARAMETERS:  HowLong             - The amount of time to stall,
+ *                                    in microseconds
  *
  * RETURN:      Status
  *
  * DESCRIPTION: Suspend running thread for specified amount of time.
+ *              Note: ACPI specification requires that Stall() does not
+ *              relinquish the processor, and delays longer than 100 usec
+ *              should use Sleep() instead.  We allow stalls up to 255 usec
+ *              for compatibility with other interpreters and existing BIOSs.
  *
  ******************************************************************************/
 
@@ -206,19 +211,17 @@ AcpiExSystemDoStall (
     ACPI_FUNCTION_ENTRY ();
 
 
-    if (HowLong > 1000) /* 1 millisecond */
+    if (HowLong > 255) /* 255 microseconds */
     {
-        /* Since this thread will sleep, we must release the interpreter */
-
-        AcpiExExitInterpreter ();
-
-        AcpiOsSleep (0, (HowLong / 1000) + 1);
-
-        /* And now we must get the interpreter again */
-
-        Status = AcpiExEnterInterpreter ();
+        /*
+         * Longer than 255 usec, this is an error
+         *
+         * (ACPI specifies 100 usec as max, but this gives some slack in
+         * order to support existing BIOSs)
+         */
+        ACPI_REPORT_ERROR (("Stall: Time parameter is too large (%d)\n", HowLong));
+        Status = AE_AML_OPERAND_VALUE;
     }
-
     else
     {
         AcpiOsStall (HowLong);
@@ -232,7 +235,8 @@ AcpiExSystemDoStall (
  *
  * FUNCTION:    AcpiExSystemDoSuspend
  *
- * PARAMETERS:  HowLong             - The amount of time to suspend
+ * PARAMETERS:  HowLong             - The amount of time to suspend,
+ *                                    in milliseconds
  *
  * RETURN:      None
  *