From a45a8c8571c0be6a6bd72ae5a14255c26b14b504 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Fri, 16 Sep 2011 21:24:02 +0200 Subject: [PATCH] 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 Cc: Fenghua Yu Cc: "R, Durgadoss" Cc: Guenter Roeck Cc: Alexander Stein Acked-by: Fenghua Yu Signed-off-by: Guenter Roeck --- Documentation/hwmon/coretemp | 7 ++++--- drivers/hwmon/coretemp.c | 15 +++++++++++++++ 2 files changed, 19 insertions(+), 3 deletions(-) diff --git a/Documentation/hwmon/coretemp b/Documentation/hwmon/coretemp index fa8776ab9b18..49c0d42dde86 100644 --- a/Documentation/hwmon/coretemp +++ b/Documentation/hwmon/coretemp @@ -49,9 +49,10 @@ tempX_label - Contains string "Core X", where X is processor number. For Package temp, this will be "Physical id Y", where Y is the package number. -The TjMax temperature is set to 85 degrees C if undocumented model specific -register (UMSR) 0xee has bit 30 set. If not the TjMax is 100 degrees C as -(sometimes) documented in processor datasheet. +On CPU models which support it, TjMax is read from a model-specific register. +On other models, it is set to an arbitrary value based on weak heuristics. +If these heuristics don't work for you, you can pass the correct TjMax value +as a module parameter (tjmax). Appendix A. Known TjMax lists (TBD): Some information comes from ark.intel.com 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 #include #include +#include #include #include #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. -- 2.20.1