hwmon/coretemp: Add more safety checks
Add detection of AE18 Errata of Core processor and warns
users that the absolute readings might be wrong for Core2 processor.
Signed-off-by: Rudolf Marek <r.marek@assembler.cz>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index 75e3911..0328382 100644
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -176,6 +176,22 @@
goto exit_free;
}
+ /* Check if we have problem with errata AE18 of Core processors:
+ Readings might stop update when processor visited too deep sleep,
+ fixed for stepping D0 (6EC).
+ */
+
+ if ((c->x86_model == 0xe) && (c->x86_mask < 0xc)) {
+ /* check for microcode update */
+ rdmsr_on_cpu(data->id, MSR_IA32_UCODE_REV, &eax, &edx);
+ if (edx < 0x39) {
+ dev_err(&pdev->dev,
+ "Errata AE18 not fixed, update BIOS or "
+ "microcode of the CPU!\n");
+ goto exit_free;
+ }
+ }
+
/* Some processors have Tjmax 85 following magic should detect it
Intel won't disclose the information without signed NDA, but
individuals cannot sign it. Catch(ed) 22.
@@ -193,6 +209,19 @@
}
}
+ /* Intel says that above should not work for desktop Core2 processors,
+ but it seems to work. There is no other way how get the absolute
+ readings. Warn the user about this. First check if are desktop,
+ bit 50 of MSR_IA32_PLATFORM_ID should be 0.
+ */
+
+ rdmsr_safe_on_cpu(data->id, MSR_IA32_PLATFORM_ID, &eax, &edx);
+
+ if ((c->x86_model == 0xf) && (!(edx & 0x00040000))) {
+ dev_warn(&pdev->dev, "Using undocumented features, absolute "
+ "temperature might be wrong!\n");
+ }
+
platform_set_drvdata(pdev, data);
if ((err = sysfs_create_group(&pdev->dev.kobj, &coretemp_group)))
@@ -330,9 +359,6 @@
int i, err = -ENODEV;
struct pdev_entry *p, *n;
- printk(KERN_NOTICE DRVNAME ": This driver uses undocumented features "
- "of Core CPU. Temperature might be wrong!\n");
-
/* quick check if we run Intel */
if (cpu_data[0].x86_vendor != X86_VENDOR_INTEL)
goto exit;