drivers/hwmon/coretemp.c: detect the thermal sensors by CPUID

Carsten Emde · torvalds · commit 5db47b009d17 · 2010-05-25T08:07:07.000-07:00
The thermal sensors of Intel(R) CPUs can be detected by CPUID instruction,
indicated by CPUID.06H.EAX[0].

Signed-off-by: Huaxu Wan &lt;huaxu.wan@linux.intel.com&gt;
Signed-off-by: Carsten Emde &lt;C.Emde@osadl.org&gt;
Reviewed-by: Valdis Kletnieks &lt;valdis.kletnieks@vt.edu&gt;
Cc: Jean Delvare &lt;khali@linux-fr.org&gt;
Cc: Henrique de Moraes Holschuh &lt;hmh@hmh.eng.br&gt;
Cc: Yong Wang &lt;yong.y.wang@linux.intel.com&gt;
Cc: Rudolf Marek &lt;r.marek@assembler.cz&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
@@ -451,28 +451,20 @@ static int __init coretemp_init(void)
 
 	for_each_online_cpu(i) {
 		struct cpuinfo_x86 *c = &cpu_data(i);
+		/*
+		 * CPUID.06H.EAX[0] indicates whether the CPU has thermal
+		 * sensors. We check this bit only, all the early CPUs
+		 * without thermal sensors will be filtered out.
+		 */
+		if (c->cpuid_level >= 6 && (cpuid_eax(0x06) & 0x01)) {
+			err = coretemp_device_add(i);
+			if (err)
+				goto exit_devices_unreg;
 
-		/* check if family 6, models 0xe (Pentium M DC),
-		  0xf (Core 2 DC 65nm), 0x16 (Core 2 SC 65nm),
-		  0x17 (Penryn 45nm), 0x1a (Nehalem), 0x1c (Atom),
-		  0x1e (Lynnfield) */
-		if ((c->cpuid_level < 0) || (c->x86 != 0x6) ||
-		    !((c->x86_model == 0xe) || (c->x86_model == 0xf) ||
-			(c->x86_model == 0x16) || (c->x86_model == 0x17) ||
-			(c->x86_model == 0x1a) || (c->x86_model == 0x1c) ||
-			(c->x86_model == 0x1e))) {
-
-			/* supported CPU not found, but report the unknown
-			   family 6 CPU */
-			if ((c->x86 == 0x6) && (c->x86_model > 0xf))
-				printk(KERN_WARNING DRVNAME ": Unknown CPU "
-					"model 0x%x\n", c->x86_model);
-			continue;
+		} else {
+			printk(KERN_INFO DRVNAME ": CPU (model=0x%x)"
+				" has no thermal sensor.\n", c->x86_model);
 		}
-
-		err = coretemp_device_add(i);
-		if (err)
-			goto exit_devices_unreg;
 	}
 	if (list_empty(&pdev_list)) {
 		err = -ENODEV;
