Author: avg
Date: Sat Dec 1 18:06:05 2012
New Revision: 243761
URL: http://svnweb.freebsd.org/changeset/base/243761
Log:
acpi_cpu_notify: disable acpi_cpu_idle while updating C-state data
... to avoid any races or inconsistencies.
This should fix a regression introduced in r243404.
Also, remove a stale comment that has not been true for quite a while
now.
Pointyhat to: avg
Teested by: trociny, emaste, dumbbell (earlier version)
MFC after: 1 week
Modified:
head/sys/dev/acpica/acpi_cpu.c
Modified: head/sys/dev/acpica/acpi_cpu.c
==============================================================================
--- head/sys/dev/acpica/acpi_cpu.c Sat Dec 1 18:01:01 2012
(r243760)
+++ head/sys/dev/acpica/acpi_cpu.c Sat Dec 1 18:06:05 2012
(r243761)
@@ -973,9 +973,9 @@ acpi_cpu_idle()
return;
}
- /* If disabled, return immediately. */
+ /* If disabled, take the safe path. */
if (is_idle_disabled(sc)) {
- ACPI_ENABLE_IRQS();
+ acpi_cpu_c1();
return;
}
@@ -1081,23 +1081,31 @@ acpi_cpu_idle()
/*
* Re-evaluate the _CST object when we are notified that it changed.
- *
- * XXX Re-evaluation disabled until locking is done.
*/
static void
acpi_cpu_notify(ACPI_HANDLE h, UINT32 notify, void *context)
{
struct acpi_cpu_softc *sc = (struct acpi_cpu_softc *)context;
-
+
if (notify != ACPI_NOTIFY_CX_STATES)
return;
+ /*
+ * C-state data for target CPU is going to be in flux while we execute
+ * acpi_cpu_cx_cst, so disable entering acpi_cpu_idle.
+ * Also, it may happen that multiple ACPI taskqueues may concurrently
+ * execute notifications for the same CPU. ACPI_SERIAL is used to
+ * protect against that.
+ */
+ ACPI_SERIAL_BEGIN(cpu);
+ disable_idle(sc);
+
/* Update the list of Cx states. */
acpi_cpu_cx_cst(sc);
acpi_cpu_cx_list(sc);
-
- ACPI_SERIAL_BEGIN(cpu);
acpi_cpu_set_cx_lowest(sc);
+
+ enable_idle(sc);
ACPI_SERIAL_END(cpu);
acpi_UserNotify("PROCESSOR", sc->cpu_handle, notify);
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