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authorJean Delvare <khali@linux-fr.org>2011-09-16 21:24:02 +0200
committerGuenter Roeck <guenter.roeck@ericsson.com>2011-09-21 17:25:18 -0700
commita45a8c8571c0be6a6bd72ae5a14255c26b14b504 (patch)
tree47593c6b73c9a68dce03b57e7a387f94f441b8bb /drivers/hwmon/coretemp.c
parent6bf9e9b09c3abb5447bbbf16c2d0cbe721e44f3f (diff)
hwmon: (coretemp) Let the user force TjMax
On old CPUs (and even some recent Atom CPUs) TjMax can't be read from the CPU registers, so it is guessed by the driver using a complex heuristic which isn't reliable. So let users who know their CPU's TjMax pass it as a module parameter. Signed-off-by: Jean Delvare <khali@linux-fr.org> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: "R, Durgadoss" <durgadoss.r@intel.com> Cc: Guenter Roeck <guenter.roeck@ericsson.com> Cc: Alexander Stein <alexander.stein@systec-electronic.com> Acked-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Diffstat (limited to 'drivers/hwmon/coretemp.c')
-rw-r--r--drivers/hwmon/coretemp.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index 256f70803eb3..5a41e9dda909 100644
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -36,11 +36,20 @@
#include <linux/cpu.h>
#include <linux/pci.h>
#include <linux/smp.h>
+#include <linux/moduleparam.h>
#include <asm/msr.h>
#include <asm/processor.h>
#define DRVNAME "coretemp"
+/*
+ * force_tjmax only matters when TjMax can't be read from the CPU itself.
+ * When set, it replaces the driver's suboptimal heuristic.
+ */
+static int force_tjmax;
+module_param_named(tjmax, force_tjmax, int, 0444);
+MODULE_PARM_DESC(tjmax, "TjMax value in degrees Celsius");
+
#define BASE_SYSFS_ATTR_NO 2 /* Sysfs Base attr no for coretemp */
#define NUM_REAL_CORES 16 /* Number of Real cores per cpu */
#define CORETEMP_NAME_LENGTH 17 /* String Length of attrs */
@@ -398,6 +407,12 @@ static int get_tjmax(struct cpuinfo_x86 *c, u32 id, struct device *dev)
}
}
+ if (force_tjmax) {
+ dev_notice(dev, "TjMax forced to %d degrees C by user\n",
+ force_tjmax);
+ return force_tjmax * 1000;
+ }
+
/*
* An assumption is made for early CPUs and unreadable MSR.
* NOTE: the calculated value may not be correct.