acpi_thermal: fix _AL activation logic

[Andriy Gapon]

The following patch should put the logic in acpi_thermal in accordance to my
understanding of ACPI specification.  This is probably of very minor importance as
very few modern systems use ACPI TZ to managed fans (this is mostly deferred to
hardware or firmware).  The change would probably change nothing for systems where
a TZ manages a single fan with various speed levels.

commit 8da38fffb44ddf5449e5fc15d3ad07b645de12f8
Author: Andriy Gapon <avg at icyb.net.ua>
Date:   Wed Sep 26 18:26:47 2012 +0300

    acpi_thermal: when _ACx is tripped, all _ALi i>= x should be on

    ... and not just _ALx as it is now.

diff --git a/sys/dev/acpica/acpi_thermal.c b/sys/dev/acpica/acpi_thermal.c
index 32e5c2d..baa8205 100644
--- a/sys/dev/acpica/acpi_thermal.c
+++ b/sys/dev/acpica/acpi_thermal.c
@@ -121,6 +121,8 @@ struct acpi_tz_softc {
     int				tz_cooling_saved_freq;
 };

+#define	TZ_ACTIVE_LEVEL(act)	((act) >= 0 ? (act) : TZ_NUMLEVELS)
+
 #define CPUFREQ_MAX_LEVELS	64 /* XXX cpufreq should export this */

 static int	acpi_tz_probe(device_t dev);
@@ -565,18 +567,21 @@ acpi_tz_monitor(void *Context)
     }

     if (newactive != sc->tz_active) {
-	/* Turn off the cooling devices that are on, if any are */
-	if (sc->tz_active != TZ_ACTIVE_NONE)
+	/* Turn off unneeded cooling devices that are on, if any are */
+	for (i = TZ_ACTIVE_LEVEL(sc->tz_active);
+	     i < TZ_ACTIVE_LEVEL(newactive); i++) {
 	    acpi_ForeachPackageObject(
-		(ACPI_OBJECT *)sc->tz_zone.al[sc->tz_active].Pointer,
+		(ACPI_OBJECT *)sc->tz_zone.al[i].Pointer,
 		acpi_tz_switch_cooler_off, sc);
-
+	}
 	/* Turn on cooling devices that are required, if any are */
-	if (newactive != TZ_ACTIVE_NONE) {
+	for (i = TZ_ACTIVE_LEVEL(sc->tz_active) - 1;
+	     i >= TZ_ACTIVE_LEVEL(newactive); i--) {
 	    acpi_ForeachPackageObject(
-		(ACPI_OBJECT *)sc->tz_zone.al[newactive].Pointer,
+		(ACPI_OBJECT *)sc->tz_zone.al[i].Pointer,
 		acpi_tz_switch_cooler_on, sc);
 	}
+
 	ACPI_VPRINT(sc->tz_dev, acpi_device_get_parent_softc(sc->tz_dev),
 		    "switched from %s to %s: %d.%dC\n",
 		    acpi_tz_aclevel_string(sc->tz_active),

-- 
Andriy Gapon