Revert "hwmon: (coretemp) Refine TjMax detection"

This reverts commit 82b5e642c6cabdb95e1ef5ba05767af686404909.

Tjmax on some Intel CPUs is below 85 degrees C. One known example is
L5630 with Tjmax of 71 degrees C. There are other Xeon processors with
Tjmax of 70 or 80 degrees C. Also, the Intel IA32 System Programming
document states that the temperature target is in bits 23:16 of MSR 0x1a2
(MSR_TEMPERATURE_TARGET), which is 8 bits, not 7.

So even if turbostat uses similar checks to validate Tjmax, there is no
evidence that the checks are actually required. On the contrary, the
checks are known to cause problems and therefore need to be removed.

This fixes https://bugzilla.kernel.org/show_bug.cgi?id=75071.

Fixes: 82b5e64 hwmon: (coretemp) Refine TjMax detection
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Cc: stable@vger.kernel.org # 3.14+
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/coretemp.c b/drivers/hwmon/coretemp.c
index 6d02e3b063756f6225078df7e00f981478ef5f45..d76f0b70c6e09a0dd4bf52d77df7aa85651377c9 100644 (file)
--- a/drivers/hwmon/coretemp.c
+++ b/drivers/hwmon/coretemp.c
@@ -365,12 +365,12 @@ static int get_tjmax(struct cpuinfo_x86 *c, u32 id, struct device *dev)
                if (cpu_has_tjmax(c))
                        dev_warn(dev, "Unable to read TjMax from CPU %u\n", id);
        } else {
-               val = (eax >> 16) & 0x7f;
+               val = (eax >> 16) & 0xff;
                /*
                 * If the TjMax is not plausible, an assumption
                 * will be used
                 */
-               if (val >= 85) {
+               if (val) {
                        dev_dbg(dev, "TjMax is %d degrees C\n", val);
                        return val * 1000;
                }