Mon Aug 9 05:00:24 2010 UTC ()

Downgrade the currently supported maximum C-state to C1. There appears to be
timer-related interrupt issues also in C2. With C1 it is guaranteed that
acpicpu(4) will not cause any slowdowns due stalled local APIC timer.


(jruoho)

diff -r1.16 -r1.17 src/sys/dev/acpi/acpi_cpu_cstate.c

--- src/sys/dev/acpi/acpi_cpu_cstate.c 2010/08/08 18:25:06	1.16
+++ src/sys/dev/acpi/acpi_cpu_cstate.c 2010/08/09 05:00:24	1.17

 @@ -1,14 +1,14 @@
-/* $NetBSD: acpi_cpu_cstate.c,v 1.16 2010/08/08 18:25:06 jruoho Exp $ */
+/* $NetBSD: acpi_cpu_cstate.c,v 1.17 2010/08/09 05:00:24 jruoho Exp $ */
 /*-
  * Copyright (c) 2010 Jukka Ruohonen <jruohonen@iki.fi>
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
+ *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
 @@ -17,27 +17,27 @@
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: acpi_cpu_cstate.c,v 1.16 2010/08/08 18:25:06 jruoho Exp $");
+__KERNEL_RCSID(0, "$NetBSD: acpi_cpu_cstate.c,v 1.17 2010/08/09 05:00:24 jruoho Exp $");
 #include <sys/param.h>
 #include <sys/cpu.h>
 #include <sys/device.h>
 #include <sys/kernel.h>
 #include <sys/once.h>
 #include <sys/mutex.h>
 #include <sys/timetc.h>
 #include <dev/pci/pcivar.h>
 #include <dev/pci/pcidevs.h>
 #include <dev/acpi/acpireg.h>
 @@ -55,33 +55,35 @@ static ACPI_STATUS	 acpicpu_cstate_cst(s
 static ACPI_STATUS	 acpicpu_cstate_cst_add(struct acpicpu_softc *,
 						ACPI_OBJECT *);
 static void		 acpicpu_cstate_cst_bios(void);
 static void		 acpicpu_cstate_fadt(struct acpicpu_softc *);
 static void		 acpicpu_cstate_quirks(struct acpicpu_softc *);
 static int		 acpicpu_cstate_quirks_piix4(struct pci_attach_args *);
 static int		 acpicpu_cstate_latency(struct acpicpu_softc *);
 static bool		 acpicpu_cstate_bm_check(void);
 static void		 acpicpu_cstate_idle_enter(struct acpicpu_softc *,int);
 extern struct acpicpu_softc **acpicpu_sc;
 /*
- * XXX:	The local APIC timer (as well as TSC) is typically
+ * XXX:	The local APIC timer (as well as TSC) is typically stopped in C3.
- *	stopped in C3. For now, we cannot but disable C3.
+ *	For now, we cannot but disable C3. But there appears to be timer-
  *	related interrupt issues also in C2. The only entirely safe option
  *	at the moment is to use C1.
  */
 #ifdef ACPICPU_ENABLE_C3
 static int cs_state_max = ACPI_STATE_C3;
 #else
-static int cs_state_max = ACPI_STATE_C2;
+static int cs_state_max = ACPI_STATE_C1;
 #endif
 void
 acpicpu_cstate_attach(device_t self)
+{
 	struct acpicpu_softc *sc = device_private(self);
 	ACPI_STATUS rv;
 	/*
 	 * Either use the preferred _CST or resort to FADT.
 	 */
 	rv = acpicpu_cstate_cst(sc);