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

The thermal sensors of Intel(R) CPUs can be detected by CPUID instruction,
indicated by CPUID.06H.EAX[0].

Signed-off-by: Huaxu Wan <huaxu.wan@linux.intel.com>
Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Reviewed-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Yong Wang <yong.y.wang@linux.intel.com>
Cc: Rudolf Marek <r.marek@assembler.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index e9b7fbc5a4476b9cfdb2bd01ec58719b097cf7cb..9fae7cbc5d768ac11863a17022ab335755080f46 100644 (file)
--- 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;